A researcher wants to prove that there is a difference in the average age of onset of a certain disease for men and women who get the disease.

A random sample of 30 women with the disease showed an average age of onset of 83 years, with a sample standard deviation of 11 years. A random sample of 20 men with the disease showed an average age of onset of 77 years, with a sample standard deviation of 4 years.

Assume that ages at onset of this disease are normally distributed for each gender, and that they are independent of each other

Suppose that a difference between two groups is examined.

In comparing a breakup and a surface count of the number of choc chips in a cookie, a researcher takes four cookies of one type and records the following data:

Find the mean of the difference (breakup count - surface count), correct to two decimal places.

In testing the hypotheses H₀:mu=10 against H_A:mu not =10,

a sample of size 16 was used and gave a standardized score for the sample (a t-statistic) of 1.30.

The associated P-value

A one-sample Z-test with a 1-tailed alternative hypothesis was carried out.

A z-statistic of -1.32 has been calculated for the sample mean.

An hypothesis test had hypotheses:  H₀:µ = 10 against H_A:µ  not = 10  at a level of significance of 0.05.

A 95% confidence interval for the mean was calculated to be (9.61, 9.93).

Which of the following conclusion is the best for this situation?

A random sample of 27 adults had a sample mean height of 168 cms with a sample standard deviation of 10 cms. The standard error (from the standard deviation of the sampling distribution) of the sample mean height, correct to one decimal place, is