Question 1 (2 points)                

When a difference is not statistically significant, there are two possibilities. Select the two possibilities:

  Question 1 options:

Type I error

The hypothesis was incorrectly written

Type II error

The null hypothesis is true

 

Question 2 (2 points)                

If a researcher makes a Type I error, the researcher has:

  Question 2 options:

Drawn a conclusion that there is no difference between the experimental and control groups when in fact a difference exists

Drawn a conclusion that there is a difference between the experimental and control groups when no difference exists

 

Question 3 (2 points)                

If a researcher makes a Type II error, the researcher has:

  Question 3 options:

Drawn a conclusion that there is no difference between the experimental and control groups when in fact a difference exists

Drawn a conclusion that there is a difference between the experimental and control groups when no difference exists

You read a research report of the differences in weight gain in infants on enriched formula (sample 1) and soy-based formula (sample 2). The findings are reported as: t=6.79; p=.006; Confidence interval of the mean difference: 4.76 to 8.43.

What is the hypothesis decision?

Reject the null hypothesis

Accept the null hypothesis

Sample 2 is larger than sample 1: the soy-based formula showed greater weight gain in infants than the enriched formula

Sample 1 is larger than sample 2: the enriched formula showed greater weight gain in infants than the soy-based formula

You read a research report of the differences in weight gain in infants on enriched formula (sample 1) and soy-based formula (sample 2). The findings are reported as: t=6.79; p=.006; Confidence interval of the mean difference: 4.76 to 8.43.

What is the conclusion statement?

Accept the null hypothesis

Sample 2 is larger than sample 1: the soy-based formula showed greater weight gain in infants than the enriched formula

Reject the null hypothesis

Sample 1 is larger than sample 2: the enriched formula showed greater weight gain in infants than the soy-based formula

You read a research report in which the confidence interval of the mean difference is reported as -1.45 to 3.46. You know from this information that:

There is no statistically significant differences between samples

There is a statistically significant difference between samples; the mean of sample 1 is larger than the mean of sample 2

There is a statistically significant difference between samples; the mean of sample 1 is smaller than the mean of sample 2

The following table depicts the four possible outcomes of a hypothesis test: The researcher makes a correct decision (either by correctly rejecting the null hypothesis or correctly not rejecting the null hypothesis), makes a Type I error, or makes a Type II error. In each of the following boxes, select the description that matches the outcome.

The probability of a Type I error is ......, and the probability of a Type II error is.

 Possible outcomes of a hypothesis test:

The following table depicts the four possible outcomes of a hypothesis test: The researcher makes a correct decision ther by correctly rejecting the null hypothesis or correctly not rejecting the null hypothesis, makes a Type I or, or makes a Type II error. In each of the following boxes, select the description that matches the outcome.

The probability of a Type I error is , and the probability of a Type II error is.........

For his Statistics class experiment, researcher J. Gilbert decided to study how parents’ income affects children’s performance on standardized tests like the SAT. He proposed to collect information from a random sample of test takers and examine the relationship between parental income and SAT score.

a) Is this an experiment? If not, what kind of study is it?

b) If there is relationship between parental income and SAT score, why can’t we conclude that differences in score are caused by differences in parental income?