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PYC3714-25-S2
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Suppose H0: m = 100 is tested against H1: μ ¹ 100 with α = 0.05. If the t-statistic is found to be -3.20 and the two-tailed p-value is 0.04, what decision regarding the statistical hypothesis can be taken?
- - - - - sample involves selecting individuals at fixed intervals whereas - - - - - sampling involves dividing the population into homogenous subgroups and then drawing samples from these subgroups.
A group of middle managers in a company are required to undergo a training programme aimed at improving their leadership abilities. A researcher wants to establish the effectiveness of the training programme. She tests each participant before the training commences on a questionnaire that measures the leadership ability of each participant as well as on their score on a scale that measures self-esteem. After the training programme is completed, each participant is again tested for their leadership ability. The table below shows the results of the measurements.
Case
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Gender
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1
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1
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1
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1
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1
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2
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2
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2
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SelfEst
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5
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4
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1
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5
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2
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2
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2
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3
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Lead1
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5
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3
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6
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5
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4
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4
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4
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5
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5
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1
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6
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Lead2
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6
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7
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Key:
The variable Gender is coded with 1 = Male; 2 = Female.
SelfEst is a variable indicating self-esteem and was measured on a 5-point scale (ranging from 1=’low self-esteem’ to 5=’high self-esteem’).
Leadership ability was
measured twice on a 7-point scale (with 1=’very low leadership ability’ up to
7=’very high leadership ability’).
Lead1indicates the measurement before the training programme, while
Lead2represents the measurement
thereafter.
The researcher calculates the value of the appropriate test statistic based on a hypothesis developed given all the information in the case study. In which of the four intervals below will the absolute value of the test statistic fall (i.e., ignoring a plus or minus sign)?
A researcher hypothesizes that the drug treatment of hospitalised schizophrenic patients improves their mental alertness. He studies a random sample of 27 patients to see whether there is a relationship between the number of days of drug treatment and patients’ scores on the Mental Alertness Test.
Which is an appropriate
null hypothesis for this research?
What does it mean to say “the difference between the means of groups A and B is not statistically significant”?
A group of middle managers in a company are required to undergo a training programme aimed at improving their leadership abilities. A researcher wants to establish the effectiveness of the training programme. She tests each participant before the training commences on a questionnaire that measures the leadership ability of each participant as well as on their score on a scale that measures self-esteem. After the training programme is completed, each participant is again tested for their leadership ability. The table below shows the results of the measurements.
Case
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Gender
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1
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1
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1
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1
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1
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1
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1
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1
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1
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2
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2
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2
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2
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2
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2
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2
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2
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SelfEst
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5
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4
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3
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1
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3
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4
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5
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3
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2
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2
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3
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3
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4
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2
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2
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3
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3
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Lead1
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5
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4
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3
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3
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4
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6
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5
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4
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4
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4
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5
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4
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5
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1
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2
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3
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6
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Lead2
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6
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6
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3
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6
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7
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4
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5
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4
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6
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7
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6
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5
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3
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4
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5
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5
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Key:
The variable Gender is coded with 1 = Male; 2 = Female.
SelfEst is a variable indicating self-esteem and was measured on a 5-point scale (ranging from 1=’low self-esteem’ to 5=’high self-esteem’).
Leadership ability was
measured twice on a 7-point scale (with 1=’very low leadership ability’ up to
7=’very high leadership ability’).
Lead1indicates the measurement before the training programme, while
Lead2represents the measurement
thereafter.
Which of the following is the result if this test statistic (using all the information in the case study) is calculated? The value of the test statistic will fall - - - - -.
Which one of the following statements about a sample are false?
A group of middle managers in a company are required to undergo a training programme aimed at improving their leadership abilities. A researcher wants to establish the effectiveness of the training programme. She tests each participant before the training commences on a questionnaire that measures the leadership ability of each participant as well as on their score on a scale that measures self-esteem. After the training programme is completed, each participant is again tested for their leadership ability. The table below shows the results of the measurements.
Case
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1
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3
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4
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5
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6
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7
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8
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9
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10
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14
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15
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16
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17
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Gender
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1
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1
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1
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1
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1
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1
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1
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1
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1
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2
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2
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2
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2
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2
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2
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2
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2
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SelfEst
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5
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4
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3
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1
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3
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4
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5
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3
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2
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2
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3
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3
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4
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2
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2
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3
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3
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Lead1
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5
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4
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3
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3
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4
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6
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5
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4
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4
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4
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5
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4
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5
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1
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2
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3
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6
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Lead2
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6
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6
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3
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4
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6
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7
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4
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5
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4
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6
|
7
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6
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5
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3
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4
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5
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5
|
Key:
The variable Gender is coded with 1 = Male; 2 = Female.
SelfEst is a variable indicating self-esteem and was measured on a 5-point scale (ranging from 1=’low self-esteem’ to 5=’high self-esteem’).
Leadership ability was
measured twice on a 7-point scale (with 1=’very low leadership ability’ up to
7=’very high leadership ability’).
Lead1indicates the measurement before the training programme, while
Lead2represents the measurement
thereafter.
Assuming that the data is normally distributed and the variances do not differ significantly, which of the following tests are appropriate to test the hypotheses in the case study?
A researcher plans to use the t-test to compare two independent samples of data of only 15 individuals each. Consider the following assumptions that may be relevant here:
(a) the sample standard deviations have to be equal
(b) the data from both samples has to come from populations that are normally distributed
What minimum assumptions from the ones given above needs to be met before she may proceed?
When using a t-test to compare the means from two samples of data, a researcher finds a significant difference. She decides to also determine the effect size of the result. For what reason would she do this?