Which of the following is not a requirement for making a claim that A causes B?

A scientist is researching the effects of a new supplement on memory improvements. They are comparing the effects of Supplement A and Supplement B (a placebo) on memory of list words. They had participants memorise a list of words and complete a recall task where they write down as many words as they can remember. One day later the participants completed the same task after taking Supplement A or Supplement B.

What is the independent variable in this example?

Helen has been counting the number of drinks people have at a bar to assess how depressed they are and says that people drinking more at the bar are more depressed. Helen's measurement is:

Which of the following is NOT a characteristic of the independent variable?

Tim has been examining whether owning a dog increases happiness. He found people with dogs are happier. There is an issue for internal validity here due to _________________.

My friend and I are counting how many people enter the local pub between 5pm and 6pm on one Friday night. I counted that 30 people entered the pub, but my friend counted that 45 people entered the pub. Our measurements are________

My set of scales at home always tells me that I am 65kg. I weigh myself three times a week and this is always the measurement. When I weighed myself at the GPs today I was actually 62kg.

What does this say about the reliability and validity of my home scales?

A recent study examined the relationship between listening to classical music and average income. They found listening to classical music was positively correlated with higher income. There is an issue with _______________ validity in this study.

Population validity and ecological validity are different forms of:

Intelligence tests contain many different questions that assess the same underlying construct. Given that there are so many questions, a good intelligence test should be high on: