Quant Test 1

A survey of 800 college seniors resulted in the following cross tabulation regarding their undergraduate major and whether or not they plan to go to graduate school. Of those students who are majoring in business, what percentage plans to go to graduate school? Business total 252, yes 70, no 182 a) 27.87 b) 8.75 c) 70.00 d) 72.22

A) 27.78

In a questionnaire, respondents are asked to mark their gender as male or female. Gender is an example of a(n): a) categorical variable b) quantitative variable c) interval-scale variable d) ordinal-scale variable

A) categorical variable

The collection of all possible sample points in an experiment is: a) the sample space b) an event c) a combination d) the population

A) the sample space

A researcher has collected the following sample data. The mean of the sample is 5. [3 5 12 3 2 ] The lower is quartile: a) 2 b) 2.5 c) 3 d) 12

B) 2.5

The ages of students at a university are normally distributed with a mean of 21. What percentage of the student body is at least 21 years old? a) It could be any value, depending on the magnitude of the standard deviation b) 50% c) 21% d) 1.96%

B) 50%

Which of the following statements is always true? a) -1<P(Ei)<1 b) P(A)=a-P(Ac) c) P(A)+P(B)=1 d) Sum P>1

B) P(A)=1-P(Ac)

Which of the following is a required condition for a discrete probability function? a) f(x) < 0 for all values of x b) Sum f(x) = 1 for all values of x c) Sum f(x) = 0 for all values of x d) Sum f(x) > 1 for all values of x

B) Sum f(x)=1 for all values of x

The number of customers that enter a store during one day is an example of: a) a continuous random variable b) a discrete random variable c) either a continuous or a discrete random variable, depending on whether odd or even number of the customers enter d) either a continuous or a discrete random variable, depending on the gender of the customers

B) a discrete random variable

In a sample of 1,600 registered voters, 912 or 57% approve of the way the President is doing his job. The 57% approval is an example of: a) a sample b) descriptive statistics c) statistical inference d) a population

B) descriptive statistics

In a standard normal distribution, the a) mean and the standard deviation are both 1 b) mean is 0 and the standard deviation is 1 c) mean is 1 and the standard deviation is 0 d) mean and the standard deviation can have any value

B) mean is 0 and the standard deviation is 1

The number of observations will always be the same as the: a) number of variables b) number of elements c) population size d) sample size

B) number of elements

When should measures of locations and dispersion be computed from grouped data rather than from individual data values? a) as much as possible since computations are easier b) only when individual data values are unavailable c) whenever computer packages for descriptive statistics are unavailable d) only when the data are from a population

B) only when individual data values are unavailable

The area of the continuous uniform probability distribution is: a) triangular b) rectangular c) bell-shaped d) a series of vertical lines

B) rectangular

The sum of frequencies for all classes will always equal: a) 1 b) the number of elements in a data set c) the number of classes d) a value between 0 and 1

B) the number of elements in a data set

The life expectancy of a particular brand of tire is normally distributed with a mean of 40,000 and a standard deviation of 5,000 miles. What is the probability that a randomly selected tire will have a life of at least 47,500 miles? a) 0.4332 b) 0.9332 c) 0.0668 d) 0.4993

C) 0.0668

Data: a) are always numeric b) are always non-numeric c) are the raw material statistics d) are always categorical

C) are the raw materials of statistics

Data collected at the same time, or approximately the same point in time are: a) time series data b) approximate time series data c) cross-sectional data d) approximate data

C) cross-sectional data

The sum of the relative frequencies for all classes will always equal: a) the sample size b) the number of classes c) one d) any value larger than one

C) one

If X and Y are mutually exclusive events with P(A)=0.295, P(B)=0.32, then P(A|B)= a) 0.0944 b) 0.6150 c) 1.0000 d) 0.0000

D) 0.0000

If A and B are independent events with P(A)=0.38 and P(B)=0.55, then P(A|B)= a) 0.209 b) 0.000 c) 0.550 d) 0.380

D) 0.380

X is a normally distributed random variable with a mean of 8 and a standard deviation of 4. The probability that X is between 1.48 and 15.56 is a) 0.0222 b) 0.4190 c) 0.5222 d) 0.9190

D) 0.9190

The weight of football players is normally distributed with a mean of 200 pounds and a standard deviation of 25 pounds. What percent of players weigh between 180 and 220 pounds? a) 28.81% b) 0.5762% c) 0.281% d) 57.62%

D) 57.62%

The uniform distribution defined over the interval from 25 to 40 has the probability density function: a) f(x)=1/40 for all x b) f(x)=5/8 for 25<x<40 and f(x)=0 elsewhere c) f(x)=1/25 for 0<x<25 and f(x)=1/40 for 26<x<40 d) f(x)=1/15 for 25<x<40 and f(x)=0 elsewhere

D) f(x)=1/15 for 25<x<40 and f(x)=0 elsewhere

A numerical description of the outcome of an experiment is called a a) descriptive statistic b) probability function c) variance d) random variable

D) random variable

Which of the following is NOT a characteristic of the normal probability distribution? a) the mean, median, and the mode are equal b) the mean of the distribution can be negative, zero, or positive c) the distribution is symmetrical d) the standard deviation must be 1

D) the standard deviation must be 1