e - King Fahd University of Petroleum and Minerals
e - King Fahd University of Petroleum and Minerals
e - King Fahd University of Petroleum and Minerals
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STAT 211 Business Statistics I 5<br />
5. If the age distribution <strong>of</strong> customers at a major retail chain is thought to be bell-shaped with<br />
a mean equal to 43 years <strong>and</strong> a st<strong>and</strong>ard deviation equal to 7 years, the percentage <strong>of</strong><br />
customers between the ages <strong>of</strong> 29 <strong>and</strong> 50 years is:<br />
a. Approximately 81.5.<br />
b. Approximately 68.<br />
c. At least 75.<br />
d. Approximately 95.<br />
6. A recent study in the restaurant business determined that the mean tips for male waiters per<br />
hour <strong>of</strong> work are $6.78 with a st<strong>and</strong>ard deviation <strong>of</strong> $2.11. The mean tips per hour for<br />
female waiters are $7.86 with a st<strong>and</strong>ard deviation <strong>of</strong> $2.20. Based on this information,<br />
which <strong>of</strong> the following statements do we know to be true<br />
a. The distribution <strong>of</strong> tips for both males <strong>and</strong> females is right-skewed.<br />
b. The variation in tips received by females is more variable than males.<br />
c. The median tip for females exceeds that <strong>of</strong> males.<br />
d. On a relative basis, males have more variation in tips per hour than do females.<br />
7. Which <strong>of</strong> the following statements is incorrect<br />
a. The expected value <strong>of</strong> a discrete probability distribution is the long-run average<br />
value assuming the experiment will be repeated many times.<br />
b. The st<strong>and</strong>ard deviation <strong>of</strong> a discrete probability distribution measures the average<br />
variation <strong>of</strong> the r<strong>and</strong>om variable from the mean.<br />
c. The distribution is considered uniform if all the probabilities are equal.<br />
d. The mean <strong>of</strong> the probability distribution is equal to the square root <strong>of</strong> the expected<br />
value.<br />
8. If events E <strong>and</strong> F are independent with P(E) = 0.3 <strong>and</strong> P(F) = 0.5, find P(E ∪ F).<br />
a. 0.35<br />
b. 0.65<br />
c. 0.80<br />
d. None <strong>of</strong> the above.
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