NU MNS601 Statistics for Business midterm
Question 1 The numbers of hours worked (per week) by 400 statistics students are shown below. The class width for this distribution:
Number of Hours Frequency
0  9 20
10  19 80
20  29 200
30  39 100
Question 1 options:
is 9
is 10
is 39, which is: the largest value minus the smallest value or 39  0 = 39
varies from class to class
Question 2 A portion (subset) of a population is called a:
Question 2 options:
Statistic
Parameter
Variable
Sample
Question 3 Which ONE of the following is a discrete variable?
Question 3 options:
The number of packages delivered in one day by a delivery service
A person's weight, measured in pounds
The time it takes a car to accelerate from 0 to 60 m.p.h., measured in seconds
Distance, measured in feet
Question 4 The owner of a factory regularly requests a graphical summary of all employees' salaries. The graphical summary of salaries is an example of:
Question 4 options:
A sample
Descriptive statistics
Statistical inference
An experiment
Question 5 The areas under any probability distribution also represent probabilities.
Question 5 options:
True
False
Question 6 Given a normally distributed variable (x), if you know that for a value of x = 244 the zscore = 2.20, what is the probability of any x value being above 244?
Question 6 options:
0.9861
0.0139
0.0217
0.9783
Question 7 The variance of a sample of 169 observations equals 100. The standard deviation of the sample equals:
Question 7 options:
10,000
10
100
28,461
Question 8 Which measure of central tendency is at the highest point on a graph?
Question 8 options:
Mode
Range
Median
Mean
Question 9 Which of the following symbols represents the variance of the population?
Question 9 options:
σ2
Σ
Μ
s2
Question 10 Variance is equal to the square root of the standard deviation.
Question 10 options:
True
False
Question 11 The variable "miles per hour" is an example of what level of data:
Question 11 options:
Ratio
Nominal
Ordinal
Interval
Question 12 In calculating a binomial probability, which of the following is true?
Question 12 options:
p = the probability of success on each trial
x = the number of successes
n = the total number of trials in the experiment
All of the above
Question 13 Which of the following symbols represents the size of the sample?
Question 13 options:
Σ
N
X
N
Question 14 When calculating a binomial probability, the answer must be in the range of 0.00 to 1.00.
Question 14 options:
True
False
Question 15 The measure of central tendency that is the point at which half the scores fall above and half the scores fall below is the:
Question 15 options:
Mode
Range
Median
Mean
Question 16 Given a normally distributed variable (x), if you know that for a value of x = 3 the zscore = 1.02, what is the probability of any x value being below 3?
Question 16 options:
0.8461
0.1151
 0.1539
0.1539
Question 17 In constructing a frequency distribution, as the number of classes are decreased, the class width:
Question 17 options:
Decreases
Remains unchanged
Increases
Can increase or decrease depending on the data values
Question 18 The difference between a histogram and a bar chart is that:
Question 18 options:
On a histogram, the yvariable is frequency
The xvariable has a different level of measurement
On a bar chart, the columns are adjacent
None of the above
Question 19 This term refers to how data spreads out or disperses within a distribution.
Question 19 options:
Variability
Critical region
Range
Mode
Question 20 Which of the following is not a characteristic of the normal probability distribution?
Question 20 options:
The mean, median, and the mode are equal
The mean of the distribution can be negative, zero, or positive
The distribution is symmetrical
The standard deviation must be 1
Question 21 The Nobb Door Company manufactures doors for recreational vehicles. It has two conflicting objectives: It wants to build doors as small as possible to save on material costs, but to preserve its good reputation with the public, it feels obligated to manufacture doors that are tall enough for 95% of the adult population in the U.S. to pass through without stooping. In order to determine the height at which to manufacture doors, Nobb is willing to assume that the height of adults in America is normally distributed with a mean (µ) of 73 inches and standard deviation (σ) of 6 inches. How tall should Nobb's doors be?
Question 22 Here are the high temperature readings during June 2011 in Phoenix, AZ (treat these data as a sample): 84, 86, 78, 69, 94, 95, 94, 98, 89, 87, 88, 89, 92, 99, 102, 94, 92, 96, 89, 88, 87, 88, 84, 82, 87, 94, 97, 99, 102, 105. Find the mean, median, mode, range and standard deviation.
Question 23 A recent study of how Americans spend their leisure time surveyed workers employed more than 5 years. They determined the probability an employee has 2 weeks of vacation time to be 0.45, 1 week of vacation time to be 0.10, and 3 or more weeks to be 0.20. Suppose 10 workers are selected at random. What is the probability that 8 workers have 2 weeks of vacation time?

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Solution: NU MNS601 Statistics for Business midterm