The amount of time that customers wait in line during peak hours at one bank is normally distributed with a mean of 13 minutes and a standard deviation of 2 minutes.
The percentage of time that the waiting time lies between 15 and 17 minutes is equal to the area under the standard normal curve between ___ and ___.
A) 1, 2 B) -2, -1 C) 1, 1.15 D) 2, 4
Q. 2In a sample of 88 children selected randomly from one town, it is found that 8 of them suffer from asthma. Find the P-value for a hypothesis test to determine whether the proportion of all children in the town who suffer from asthma differs from 11.
A) 0.2157 B) 0.7157 C) 0.5686 D) 0.2843
Q. 3The variable measured in the experiment is called ____________ .
A) a sampling unit B) the treatment
C) the response variable D) the predictor variable
Q. 4The partially filled contingency table gives the relative frequencies of the data on age (in years) and sex from the residents of a retirement home.
Age (yrs)
60-69 70-79 Over 79 Total
Male 0.18 0.1 0.12
Female 0.2 0.1 0.3
Total 1
What percentage of residents are males over 79?
A) 11.5 B) 12 C) 6.6 D) 14
Q. 5The peak shopping time at a pet store is between 8-11:00 am on Saturday mornings. Management at the pet store randomly selected 160 customers last Saturday morning and decided to observe their shopping habits.
They recorded the number of items that a sample of the customers purchased as well as the total time the customers spent in the store. Identify the types of variables recorded by the pet store.
A) number of items - continuous; total time - continuous
B) number of items - discrete; total time - discrete
C) number of items - discrete; total time - continuous
D) number of items - continuous; total time - discrete
Q. 6Dave drives to work each morning at about the same time. His commute time is normally distributed with a mean of 47 minutes and a standard deviation of 5 minutes.
The percentage of time that his commute time is less than 54 minutes is equal to the area under the standard normal curve that lies to the ___ of __.
A) right, 1 B) left, 1.4 C) left, -1.4 D) right, 1.4
Q. 7At a tennis tournament a statistician keeps track of every serve. The statistician reported that the mean serve speed of a particular player was 100 miles per hour (mph) and the standard deviation of the serve speeds was 9 mph.
Assume that the statistician also gave us the information that the distribution of the serve speeds was bell shaped. What proportion of the player's serves are expected to be between 109 mph and 118 mph?
A) 0.95 B) 0.1350 C) 0.270 D) 0.68
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