STATS EXAM 1

Among 300 fatal car accidents, 135 were single-car crashes, 66 were two-car crashes, and 99 involved three or more cars. Calculate the percent of single car crashes.

45%

By inspection, determine which of the following sets of numbers has the smallest standard deviation.

5,5,5,5

The percent of data which lie between the lower and upper quartiles is

50%

A list of 5 pulse rates is: 70, 64, 80, 74, 92. What is the median for this list?

74

Among 300 fatal car accidents, 135 were single-car crashes, 66 were two-car crashes, and 99 involved three or more cars. Calculate the relative frequency of three car crashes.

99/300=.33

Which of the following best describes the standardized (z) score for an observation?

It is the number of standard deviations the observation falls from the mean.

Which of the following is not true of statistics?

Statistics is used to answer questions with 100% certainty.

Which of the following would indicate that a dataset is skewed to the right?

The mean is much larger than the median.

Which of the following would indicate that a dataset is not bell-shaped

The mean is much smaller than the median.

A random sample of 1,002 adults aged at least 18 years and living in the 48 contiguous states (i.e. any state in the United States excluding Alaska and Hawaii) was conducted by the Gallup Organization. The interviews were done over the telephone. The population represented by this sample was

all adult Americans in the 48 contiguous states living in a household with a phone.

What type of variable is the following? the speed of a car on a Boston tollway during rush hour traffic

continuous; quantitative

Which statistic is not resistant to an outlier in the data?

mean

Which one of these variables is a categorical variable?

opinion about legalization of marijuana

Determine whether the following value is a parameter or a statistic: In a survey conducted in the town of Atherton, 25% of adult respondents reported that they had been involved in at least one car accident in the past ten years.

statistic

A coach wants to understand the average speed of a fast pitched baseball for his pitcher, so he has his pitcher fast pitch 1 ball every day for 2 weeks, measures the speed with a radar gun, and records it. In this scenario, what is the sample that was taken from the population of interest?

the collection of speeds from each ball that the pitcher fast pitched during the data collection period (i.e. the 1 ball every day for 2 weeks)

What is the proper notation for the mean of a sample?

x bar

Is the following a quantitative variable? the temperatures of cups of coffee served at a restaurant

yes

is the following a qualitative variable? the brand of shoes an individual wears to play basketball

yes

The mean hours of sleep that students get per night is 7 hours, the standard deviation of hours of sleep is 1.7 hours, and the distribution is approximately normal. Complete the following sentence. For about 95% of students, nightly amount of sleep is between ______.

. 3.6 and 10.4 hrs

An organization would like to conduct a survey of a sample of their membership to make conclusions about the entire membership. Given that they have a limited budget, they should focus their attention on

. getting a representative sample.

Among 300 fatal car accidents, 135 were single-car crashes, 66 were two-car crashes, and 99 involved three or more cars. Calculate the relative frequency of two car crashes.

.22

Among 300 fatal car accidents, 135 were single-car crashes, 66 were two-car crashes, and 99 involved three or more cars. Calculate the relative frequency of single car crashes.

.45

Among 300 fatal car accidents, 135 were single-car crashes, 66 were two-car crashes, and 99 involved three or more cars. Calculate the percent of two car crashes.

22

The table below shows the results of a survey of students who took college prep courses who were asked to rate their high school education. Calculate the percentage of students who gave an excellent rating to their high schools. 136 OUT OF 589

23%

Among 300 fatal car accidents, 135 were single-car crashes, 66 were two-car crashes, and 99 involved three or more cars. Calculate the percent of three car crashes.

33%