2024/25 BIOSTATISTICS HYPOTHESIS TESTING
EXAM QUESTIONS WITH ALL CORRECT
ANSWERS!!
An experiment is conducted to test the claim that James Bond can taste the
difference between a Martini that is shaken and one that is stirred. What is the
null hypothesis? Answer - James Bond cannot taste the difference between a
Martini that is shaken and one that is stirred.
The probability value is the probability of obtaining a statistic as different
_____ _______ ________________ from the parameter specified in the null
hypothesis as the statistic obtained in the experiment. The probability value is
computed assuming that the null hypothesis is true. Answer - or more
different
Why do experimenters test hypotheses they think are false? Answer -
Providing data that supports a hypothesis does not mean that it is true, just
that there is no evidence that contradicts it. Providing evidence that is contrary
to a hypothesis allows you to reject that hypothesis as false.
State the null hypothesis for:
An experiment testing whether echinacea decreases the length of colds.
Answer - Echinacea increases or has no effect on the length of colds.
State the null hypothesis for:
A correlational study on the relationship between brain size and intelligence.
Answer - There is no relationship between brain size and intelligence.
, State the null hypothesis for:
An investigation of whether a self-proclaimed psychic can predict the outcome
of a coin flip. Answer - A psychic cannot predict the outcome of a coin flip.
State the null hypothesis for:
A study comparing a drug with a placebo on the amount of pain relief. (A one-
tailed test was used.) Answer - Pain relief in the placebo group is greater or
equal to pain relief in the drug group.
Assume the null hypothesis is that μ = 50 and that the graph shown is the
sampling distribution of the mean (M). Would a sample value of M= 60 be
significant in a two-tailed test at the .05 level? Roughly what value of M would
be needed to be significant? Answer - This mean would not be significant. M =
69.6 or 70 would probably be significant.
A researcher develops a new theory that predicts that vegetarians will have
more of a particular vitamin in their blood than non-vegetarians. An
experiment is conducted and vegetarians do have more of the vitamin, but the
difference is not significant. The probability value is 0.13. Should the
experimenter's confidence in the theory increase, decrease, or stay the same?
Answer - Confidence should increase
A researcher hypothesizes that the lowering in cholesterol associated with
weightloss is really due to exercise. To test this, the researcher carefully
controls for exercise while comparing the cholesterol levels of a group of
subjects who lose weight by dieting with a control group that does not diet.
The difference between groups in cholesterol is not significant. Can the
researcher claim that weight loss has no effect? Answer - No
A significance test is performed and p = .20. Why can't the experimenter claim
that the probability that the null hypothesis is true is .20? Answer - The null
EXAM QUESTIONS WITH ALL CORRECT
ANSWERS!!
An experiment is conducted to test the claim that James Bond can taste the
difference between a Martini that is shaken and one that is stirred. What is the
null hypothesis? Answer - James Bond cannot taste the difference between a
Martini that is shaken and one that is stirred.
The probability value is the probability of obtaining a statistic as different
_____ _______ ________________ from the parameter specified in the null
hypothesis as the statistic obtained in the experiment. The probability value is
computed assuming that the null hypothesis is true. Answer - or more
different
Why do experimenters test hypotheses they think are false? Answer -
Providing data that supports a hypothesis does not mean that it is true, just
that there is no evidence that contradicts it. Providing evidence that is contrary
to a hypothesis allows you to reject that hypothesis as false.
State the null hypothesis for:
An experiment testing whether echinacea decreases the length of colds.
Answer - Echinacea increases or has no effect on the length of colds.
State the null hypothesis for:
A correlational study on the relationship between brain size and intelligence.
Answer - There is no relationship between brain size and intelligence.
, State the null hypothesis for:
An investigation of whether a self-proclaimed psychic can predict the outcome
of a coin flip. Answer - A psychic cannot predict the outcome of a coin flip.
State the null hypothesis for:
A study comparing a drug with a placebo on the amount of pain relief. (A one-
tailed test was used.) Answer - Pain relief in the placebo group is greater or
equal to pain relief in the drug group.
Assume the null hypothesis is that μ = 50 and that the graph shown is the
sampling distribution of the mean (M). Would a sample value of M= 60 be
significant in a two-tailed test at the .05 level? Roughly what value of M would
be needed to be significant? Answer - This mean would not be significant. M =
69.6 or 70 would probably be significant.
A researcher develops a new theory that predicts that vegetarians will have
more of a particular vitamin in their blood than non-vegetarians. An
experiment is conducted and vegetarians do have more of the vitamin, but the
difference is not significant. The probability value is 0.13. Should the
experimenter's confidence in the theory increase, decrease, or stay the same?
Answer - Confidence should increase
A researcher hypothesizes that the lowering in cholesterol associated with
weightloss is really due to exercise. To test this, the researcher carefully
controls for exercise while comparing the cholesterol levels of a group of
subjects who lose weight by dieting with a control group that does not diet.
The difference between groups in cholesterol is not significant. Can the
researcher claim that weight loss has no effect? Answer - No
A significance test is performed and p = .20. Why can't the experimenter claim
that the probability that the null hypothesis is true is .20? Answer - The null
