28. baby talk: in a sample of 77 children, the mean age at which they
first began to combine words was 16.51 months, with a standard
deviation of 9.59 months.
a. construct a 95% confidence interval for the mean age at which
children first begin to combine words.
b. if a sample of 50 children had been studied, would you expect
the confidence interval to be wider or narrower than the interval
constructed in part (a)? explain.

The two-way table shows the number of people whose hobbies are reading or solving puzzles and who either ride a motorcycle or don’t ride a motorcycle. among people whose hobby is reading, what is the relative frequency of not riding a motorcycle? express your answer as a decimal, and round it to the nearest hundredth if necessary. enter your answer in the box. reading solving puzzles ride a motorcycle 7 3 don't ride a motorcycle 5 9

Arandom sample of 150 high school students were asked whether they have a job. the results are shown in the table. have a job do not have a job male 48 35 female 41 26 select a ord or phrase from the drop-down menus to correctly complete the statements describing the association.

Of the ones listed here, the factor that had the greatest impact on the eventual destruction of native americans' ways of life was the development of the a) automobile. b) highway. c) railroad. d) steamboat.