7.A random sample of 225 full time students at a large two-year college is taken to estimate the amount they spent on text books this semester. The sampled students spent an average of $200 with a standard deviation of $75. Thus, a 95% confidence interval for the average amount spent by all full time students at that school would be:

a.$200 $0.33

b.$200 $5

c.$200 $10

d.$200 $75

8.A marketing researcher is studying ways to entice customers in line at a cash register to buy impulse items like candy near the register. He conducts an experiment in which a customers are randomly selected to either have the cashier ask "would you like to buy anything else?" before completing the transaction or instead have the cashier ask "would you like your receipt in the bag?" The customers will also be photographed in the parking lot to see whether they drive an inexpensive or expensive car and that information will be examined to see if the value of the car might partially explain spending more or less money on impulse items - in addition to the question the cashier asks. This situation would not follow ethical guidelines for experiments because

a.It is a waste of time to look at the value of the person's car.

b.There was no opportunity for the customer to give informed consent.

c.The researcher would not be blind to which treatment the subject received.

d.Trying to find ways to entice people to do things is itself unethical.

9.33% of adult women in the State of Washington have a Bachelor's degree. Which is more likely?

a.At least 40% of a random sample of 100 adult women in Washington have a Bachelor's degree

b.At least 40% of a random sample of 1000 adult women in Washington have a Bachelor's degree

c.It doesn't matter if there are 100 or 1000 adult women in the sample, the chances would be the same

10.The Gallup Poll recently conducted a survey of 1500 randomly selected American adults and found that 34% of them were "enthusiastic about and committed to their work and workplace." They reported a 95% confidence interval of 34% 3%.If they had reported a confidence statement of 34% 1% for this same poll, then the confidence level

a.would have been greater than 95%

b.would have been less than 95%

c.would still be 95%

d.could be greater than 95% or less than 95%

11.The chance that a randomly selected two-year old child is a girl is 0.48. The chance that a randomly selected two-year old child has an ear infection is 0.04. This says the chance that a randomly selected two-year old child is a girl with an ear infection

a.= 0.0096 (= 0.48 times 0.02)

b.may be higher or lower than 0.0096 depending on whether gender and having an ear infection are mutually exclusive

c.may be higher or lower than 0.0096 depending on whether gender and having an ear infection are independent

12.Suppose you want to judge if a Department store is doing more business than usual this month. Which method below would help to remove the seasonal effect seen in retail sales in December?

a.Check whether December sales beat November sales.

b.Check whether December sales beat November sales by more than you'd expect due to chance variability .

c.Check whether December sales beat the average of November and January sales.

d.Check whether December sales beat the sales from last December.