20) A study by the National Park Service revealed that 50% of the vacationers going to the Rocky Mountain region visit Yellowstone Park, 40% visit the Grand Tetons, and 35% visit both. What is the probability that a vacationer will visit at least one of these magnificent attractions?
21) The ages of all the patients in the isolation ward of the hospital are 38, 26, 13, 41, and 22. What is the population standard deviation?
22) The distribution of a sample of the outside diameters of PVC pipes approximates a symmetrical, bell-shaped distribution. The arithmetic mean is 14.0 inches, and the standard deviation is 0.1 inches. About 68% of the outside diameters lie between what two amounts?
13.5 and 14.5 inches
13.9 and 14.1 inches
13.0 and 15.0 inches
13.8 and 14.2 inches
23) Each month the National Association of Purchasing Managers publishes the NAPM index. One of the questions asked on the survey to purchasing agents is: Do you think that the economy is expanding? Last month, of the 300 responses, 160 answered “yes” to the question. This month, 170 of the 290 responses indicated that the economy is expanding. If you’re testing to find if a larger proportion of agents believe that the economy is expanding this month, what is your computed test statistic?
z = -1.29
t = -1.25
t = -1.07
z = -1.11
24) The first card selected from a standard 52-card deck was a king. If it is returned to the deck, what is the probability that a king will be drawn on the second selection?
1/3 or 0.33
1/13 or 0.077
1/4 or 0.25
12/13 or 0.923
25) An example of a qualitative variable is _________________.
Weight of a person
Miles between oil changes
Number of children in a family
Color of ink in a pen
26) Which of the following is true regarding the normal distribution?
It has two modes.
The points of the curve meet the x-axis at z = -3 and z = 3.
It is asymmetrical.
The mean, median, and mode are all equal.
27 )What is the range of values for a coefficient of correlation?
0 to +1.0
-1.0 to +1.0 inclusive
-3 to +3 inclusive
28) Consider the following regression analysis between sales (Y in $1000) and social media advertising (X in dollars). = 55,000 + 7X
The regression equation implies that an:
increase of $1 in advertising is associated with an increase of $7,000 in sales.
increase of $1 in advertising is associated with an increase of $62,000 in sales.
increase of $7 in advertising is associated with an increase of $7,000 in sales.
increase of $1 in advertising is associated with an increase of $7 in sales.
29) When statisticians analyze sample data in order to draw conclusions about the characteristics of a population, this is referred to as:
30) What is the median of 26, 30, 24, 32, 32, 31, 27, and 29?