16. Phenobarbital and Phenytoin are both used to control childhood epilepsy. While both drugs work well for that purpose, doctors usually like Phenytoin because of the low number of side effects. However, since Phenobarbital is easier to store and costs less, it might be preferred in developing countries. Thus, researchers conducted a randomized double-blind experiment amongst 64 children in rural India (32 in each group) to test if the number of side effects would really be significantly more in children who take Phenobarbital compared with those who take Phenytoin for their epilepsy. The results of this experiment found no significant difference between the two drugs in the rate of side effects. Because of the small sample sizes in each group, critics of the experiment legitimately felt that

the estimates of the rate of side effects would be biased.

even if there was a big difference in the rate of side effects, it might not be detected.

since the results were not significant, the drugs can be assumed to have the same rate of side effects.

a lower significance level should be used (e.g., p-values would need to be under 1% instead of 5%

17.

Fifty-five (55%) percent of the students in a large statistics course are lower division (freshmen or sophomores), 25% are juniors, and the remainder are seniors. What is the chance that a randomly selected student is a senior?

5%

20%

30%

80% 18.

The average customer at a convenience store spends $14. You are going to keep track of how much is spent by the customers. Which of the following is most likely to occur?

The next 10 customers spend an average of between $10 and $18.

The next 100 customers spend an average of between $10 and $18.

The next 10 customers spend an average of exactly $14.

The next 100 customers spend an average of exactly $14. 19.

A scale by the deli of a supermarket is used to weigh meats and cheeses and price the items purchased by customers. The scale is well calibrated, very reliable, and gives an unbiased measured weight. However, when the food is weighed it is inside of a plastic bag, so the weights used to charge customers include the weight of the bag. The weights used to charge customers are then:

a biased measurement of the weight of the food.

still an unbiased measurement of the weight of the food.

less reliable as a measurement of the weight of the food.

more reliable as a measurement of the weight of the food

20.

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:

$200 $0.33

$200 $5

$200 $10

$200 $75