7 The following data represent the age in weeks at which bab

7. The following data represent the age (in weeks) at which babies first crawl based on a survey of 12 mothers.

52   47   30   30   37   44   44   56   44   35   26   39

A. Because the sample size is small, we must verify that the data come from a population that is normally distributed and that the sample size does not contains any outlies. Are the conditions for constructing a confidence interval about the mean satisfied?

a. NO, the sample contains an outlier.

b. NO, the population is not normally distributed.

c. YES, the population is normally distributed and the sample does not contain any outliers.

B. Construct a 95% confidence interval for the mean age at which a baby first crawl. Select the correct choice and fill in if needed.

a. (____, _____) Use ascending order and round to one decimal place as needed.

b. A 95% confidence interval cannot be constructed.

C. What could be done to increase the accuracy of the interval without changing the level of confidence?

a. Increase the sample.

b. Decrease the sample.

c. Either increase or decrease the sample size.

d. Nothing can be done.

Solution