9.

A recent survey found that 70% of the population own their homes. In a random sample of 140 heads of households, 98 responded that they owned their homes. At the a =0.01 level of significance, does that suggest a difference from the national proportion?

10.

To estimate a student's average score, we need to collect a sample. Assume population standard deviation is equal to 3, If we want to control the error within 0.2 with 98% confidence level, how large the sample size need to be?

11.

The number of points held by a sample of the NHL's highest scorers for both the Eastern Conference and the Western Conference is- shown below. At a =0.05, can it be concluded that there is a difference in means based on these data? Eastern Conference Western Conference 83 60 75 58 77 59 72 58 78 59 70 58 37 57 66 55