The variable of interest was the average distance separating traps-called trap spacing-developed by teams of fishermen fishing for the red spiny lobster in St. John’s. The trap spacing measurements (in meters) for a sample of 7 teams from A fishing cooperative, 8 teams from B cooperative are listed. For this problem, we are interested in comparing the mean trap spacing measurements of the two fishing cooperatives. A Cooperative: 93 99 105 94 82 70 86 B Cooperative: 118 94 106 72 90 66 153 98 a) Identify the target parameter for this study. (1) b) Computer a point estimate of the target parameter. (1) c) What is the problem with using the normal (z) statistic to find a confidence interval for the target parameter? (1) d) Find a 90% confidence interval for the target parameter. (2) e) Use the interval, part d, to make a statement about the difference in mean trap spacing measurements of the two fishing cooperatives. (1) f) What conditions must be satisfied for the inference, part e, to be valid. (1)
There has been little research on how rude behaviors influence a victim’s task performance. Students enrolled in STAT 217 were randomly assigned to one of two experimental conditions: rudeness condition (45 students) and control group (53 students). The number of different uses of a brick for each of the 98 students was recorded and saved in RUDE.TXT file. Conduct a statistical analysis (at 𝛼 = 0.01) to determine if the true mean preference level for students in the rudeness group is lower than that for students in the control group. (10)
The data for investigating the degree to which various environmental conditions affect personality saved in the TWINSIQ.TXT file. One member (A) of each of the n=32 pairs of twins was reared by a natural parent; the other member (B) was reared by a relative or some other person. Is there a significant difference between the average IQ scores of identical twins when one member of the pair is reared by the natural parents and the other member of the pair is not? Use 𝛼 = 0.05 to draw your conclusion. (10)
Enough money has been budgeted to collect independent random samples of size 𝑛1 = 𝑛2 = 100 from population 1 and 2 in order to estimate 𝑝1 − 𝑝2. Prior information indicates that 𝑝1 = 𝑝2 ≈ 0.6. Have sufficient funds been allocated to construct a 90% confidence interval for 𝑝1 − 𝑝2 of width 0.1 or less? Justify your answer. (5)