Assume that the random variable X is normally distributed, with mean = 70 and standard deviation s = 8. Compute the probability P(X < 80).
A) 0.8944 B) 0.8849 C) 0.1056 D) 0.9015
Q. 2A small computing center has found that the number of jobs submitted per day to its computers has a distribution that is approximately bell shaped, with a mean of 75 jobs and a standard deviation of 8.
Where do we expect most (approximately 95) of the distribution to fall? A) between 59 and 91 jobs per day B) between 67 and 83 jobs per day
C) between 51 and 99 jobs per day D) between 59 and 99 jobs per day
Q. 3The personnel director at a large company would like to determine whether the company cafeteria is widely used by employees.
She calls each employee and asks them whether they usually bring their own lunch, eat at the company cafeteria, or go out for lunch. A) observational study B) experiment
Q. 4A survey conducted in one U.S. city together with information from the census bureau yielded the following table. The first two columns give a percentage distribution of adults in the city by ethnic group.
The third
column gives the percentage of people in each ethnic group who have health insurance. Round to the nearest
thousandth.
Ethnic Group Percentage Percentage with
of adults health insurance
Caucasian 49.0 75
African American 12.1 46
Hispanic 18.7 51
Asian 10.8 61
Other 9.4 49
Determine the probability that a randomly selected adult has health insurance.
A) 0.630 B) 0.564 C) 0.063 D) 0.584
Q. 5Find the t-value such that the area left of the t-value is 0.01 with 8 degrees of freedom.
A) -2.896 B) -4.501 C) 2.896 D) 2.998
Q. 6Find the sum of the areas under the standard normal curve to the left of z = -1.25 and to the right of z = 1.25.
A) 0.2112 B) 0.7888 C) 0.1056 D) 0.3944
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