bus stats exam

A sample of single persons receiving Social Security payments revealed these monthly benefits: $1,077, $733, $839, $775, $913, and $798. How many observations are below the median?

3

Refer to the following information from a frequency distribution for heights of college women recorded to the nearest inch: the first two class midpoints are 62.5" and 65.5". What is the class interval?

3"

In the following set of data: (6,1,5,3,7,85,100), what are the first, second, and third quartiles?

3,6,and 85

Refer to the following frequency distribution of days absent during a calendar year by employees of a manufacturing company. days absent number of employees 0 up to 3 37 3 up to 6 33 6 up to 9 17 9 up to 12 45 12 up to 15 11 How many employees were absent fewer than six days?

70

A tire manufacturer advertises "The median life of our new all season radial tire is 50,000 miles. An immediate adjustment will be made on any tire that does not last 50,000 miles." You purchased four of these tires. What is the probability that all four tires will wear out before traveling 50,000 miles?

1/16 or .0625

The following are the weekly amounts of welfare payments made by the federal government to a sample of six families: $139, $136, $130, $136, $147, and $136. What is the range?

$17

A gumball machine has just been filled with 50 black, 150 white, 100 red, and 100 yellow gumballs that have been thoroughly mixed. Sue and Jim each purchase one gumball. What is the likelihood that both Sue and Jim will get red gumballs?

.062

A group of 100 students was surveyed about their interest in a new International Studies program. Interest was measured in terms of high, medium, or low. In the study, 30 students responded high interest, 40 students responded medium interest, and 30 students responded low interest. What is the relative frequency of students with high interest?

.30

A total of 60% of the customers of a fast food chain order a hamburger, French fries, and a drink. If a random sample of 15 cash register receipts is selected, what is the probability that 10 or more will show that the above three food items were ordered?

.403

For the following distribution x P(x) 0 0.027 1 0.189 2 0.441 3 0.343 What is the variance of the distribution?

.630

David's gasoline station offers 4 cents off per gallon if the customer pays in cash and does not use a credit card. Past evidence indicates that 40% of all customers pay in cash. During a one-hour period, 15 customers buy gasoline at this station. What is the probability that all 15 pay in cash?

0.0

If two events A and B are mutually exclusive, what does the special rule of addition state?

P(A or B) = P(A) + P(B)

A dot plot can be used to show

the distribution for a quantitative variable

A company wishes to know whether advertising expenditure is related to sales volume. Using the past two years of data for these two variables, they determined the correlation coefficient is +0.93. This indicates

a strong direct relationship between advertising expenditure and sales volume

A type of probability distribution that shows the probability of x successes and n trials, where the probability of success remains the same from trial to trial, is referred to as

binomial probability distribution

What type of variable is the number of gallons pumped by a filling station during a day?

continuous

Which of the following is an example of a continuous variable?

tons of concrete to complete a parking garage

A random variable represent the outcome of an experient. True or false

true

Quartiles divide a distribution into 10 equal parts. True or False

false

The sum of deviations of each data value from this measure of central location will always be zero.

mean

Which measures of central location are not affected by extremely small or extremely large values?

mode and median

The result of a particular experiment is called a

outcome

A small sample of computer operators shows monthly incomes of $1,950, $1,775, $2,060, $1,840, $1,795, $1,890, $1,925, and $1,810. What are these ungrouped numbers called?

raw data

When statisticians analyze sample data in order to draw conclusions about the characteristics of a population, this is referred to as

statistical inference

If Pearson's coefficient of skewness is equal to zero, the shape of the distribution is

symmetric