Question

1.The proportion of adults who own a cell phone in a certain Canadian city is believed to be 70%. Fifty adults are to be selected at random from the city. Let X be the number in the sample who own a cell phone. Under the assumptions given, the distribution of X is

A. N(50,15)N(50,15)

B. Bin(50,0.7)

C. N(35,15)N(35,15)

D. Bin(50,35)Bin(50,35)

2.

BlueSky Air has the best on-time arrival rate with 75% of its flights arriving on time. A test is conducted by randomly selecting 15 BlueSky Air flights and observing whether they arrive on time.

What is the probability that two flights of BlueSky Air arrive late? (Please carry answers to at least six decimal places in intermediate steps. Give your final answer to the nearest three decimal places).

3.

The weights of cans of Ocean brand tuna are supposed to have a net weight of 6.0 ounces. The manufacturer tells you that the net weight is actually a Normal random variable with a mean of 6.01 ounces and a standard deviation of 0.24 ounces. Suppose that you draw a random sample of 30 such cans.

Part i) Using the information about the distribution of the net weight given by the manufacturer, find the probability that the mean weight of the sample is less than 5.99 ounces. (Please carry answers to at least six decimal places in intermediate steps. Give your final answer to the nearest three decimal places).

Probability (as a proportion)

Part ii) Using the Normal approximation, which of the following is the probability that more than 51 % of the sampled cans are overweight (i.e., the net weight exceeds 6 ounces)?

A. 0.5145
B. 0.2341
C. 0.7659
D. 0.4711
E. 0.5289

Answer 1