People that grow flowers are frequently interested in increasing the growth rate of flower bushes. A retirement community wishes to test two different growth enhancement products on their azalea bushes. Each bush was assigned at random to one of the two treatments. The average growth in centimeters for each treatment was recorded. Treatment A is less expensive and will be used unless there is convincing evidence that mean growth is greater for treatment B.

a. Carry out the appropriate hypothesis test using a 0.05 significance level, and make a recommendation as to which treatment should be used.

Treatment | Sample Size | Mean (cm) | St. Dev

Type A: | 52 | 11.9 | 1.5 |

Type B: | 51 | 12.3 | 2.2 |

(b) Estimate the true difference in means using a 95% confidence interval. Does your interval support your conclusion? (Calculations only)

AP Statistics Question