TEKS.MATH.9-12.VI.C.4

Which of the following best describes a Type I error?

• The null is true, but we mistakenly reject it.

• The null is false and we reject it.

• The null is false, but we fail to reject it.

• The null is true but we fail to reject it.

• The null is true, and we fail to reject it.

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TEKS.MATH.9-12.VI.C.4

What does it mean when a test is statistically significant?

• it has reached alpha level status
• the test statistic had a P-value higher than the alpha level
• the test statistic had a P-value lower than the alpha level
• it is important in practical terms

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TEKS.MATH.9-12.VI.C.4

True or False: all samples lead to a good prediction about an entire population.

• True
• False

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TEKS.MATH.9-12.VI.C.4

To ensure that the experiment results are valid it is important that the experiment be...

• Replicated
• Controlled
• Randomized
• All of the above

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TEKS.MATH.9-12.VI.C.4

Can pleasant aromas help a student learn better? Two researchers believed that the presence of a floral scent could improve a person's learning ability in certain situations. They had 22 people work through a pencil-and-paper maze 6 times. Three of the times they wore a floral-scented mask and three times they wore an unscented mask. The three trials for each mask followed one another. Testers measures the length of time it took subjects to complete each of the six trials. They reported that, on average, subjects wearing the floral-scented mask completed the maze more quickly that those wearing the unscented mask, although, the difference was not statistically significant. This study is:

• a convenience sample
• an oberservational study
• an experiment, but not double-blind
• a double-blind experiment

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TEKS.MATH.9-12.VI.C.4

Why do we randomly select our samples?

• for control
• reduce bias
• so we don't get the same answers from everyone
• to eliminate confounding results

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TEKS.MATH.9-12.VI.C.4

Why do we randomly select our samples?

• to increase bias
• to reduce bias
• so we don't get the same answers from everyone
• because it's easier

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TEKS.MATH.7.6F

TEKS.MATH.9-12.VI.C.4

Is there bias? 
A four company wants to know what percent of local households bake at least twice a week. A company representative calls 500 randomly selected households during the daytime. 

• Yes
• No

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TEKS.MATH.9-12.VI.C.4

In a survey of 104 students, it was found that 79 went to the homecoming game this year.

A 99% confidence interval for p is (0.652, 0.868). Interpret this interval.

• 99% of the time the true proportion of people who went to the homecoming game this year is between 65.2% and 86.6%.

• The probability that the population proportion of people who went to the homecoming game this year is between 65.2% and 86.6% is 95%.

• Based on this sample, I am 99% confident that the true proportion of people who went to the homecoming game this year is between 65.2% and 86.6%.

• 99% of all possible intervals calculated this way will capture the true proportion of people who went to the homecoming game this year

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TEKS.MATH.9-12.VI.C.4

A researcher wanted to know if there is an association between exercise and sleep for the population of 16-year-olds in the United States. She obtained survey responses from a random sample of 2000 United States 16-year-olds and found convincing evidence of a positive association between exercise and sleep. Which of the following conclusions is well supported by the data?

• There is a positive association between exercise and sleep for 16-year-olds in the United States.

• There is a positive association between exercise and sleep for 16-year-olds in the world.

• Using exercise and sleep as defined by the study, an increase in sleep is caused by an increase of exercise for 16-year-olds in the United States.

• Using exercise and sleep as defined by the study, an increase in sleep is caused by an increase of exercise for 16-year-olds in the world.

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TEKS.MATH.9-12.VI.C.4