MS1023 2.1.4 Practice

A sample of 15 children shows their favorite restaurants: ​ McDonalds Luppi's Mellow Mushroom Friday's McDonalds McDonalds Pizza Hut Taco Bell McDonalds Mellow Mushroom Luppi's Pizza Hut McDonalds Friday's McDonalds ​ Which of the following is the correct relative frequency for McDonalds?

.4

Consider the following frequency distribution: Class Interval Frequency 100-under 200 25 200-under 300 45 300-under 400 30 What is the relative frequency of the second class interval?

0.45

In a frequency distribution, the first class interval begins at 18. The midpoint of the first class interval is 19.5, and the midpoint of the last class interval is 49.5. How many class intervals are there?

11

Consider the following frequency distribution: Class Interval Frequency 10-under 20 15 20-under 30 25 30-under 40 10 What is the midpoint of the first class?

15

Consider the following frequency distribution: Class Interval Frequency 100-under 200 25 200-under 300 45 300-under 400 30 What is the midpoint of the first class?

150

Consider the relative frequency distribution given below: Class Interval Frequency 20-under 40 0.2 40-under 60 0.3 60-under 80 0.4 80-under 100 0.1 There were 60 numbers in the data set. How many numbers were in the interval 40-under 60?

18

Consider the following frequency distribution: Class Interval Frequency 100-under 200 25 200-under 300 45 300-under 400 30 What is the midpoint of the last class interval?

350

n instructor made a frequency table of the scores his students got on a test Score Frequency 30-under 40 1 40-under 50 4 50-under 60 5 60-under 70 10 70-under 80 20 80-under 90 10 90-under 100 5 Approximately what percent of students got more than 70?

64

Consider the following frequency distribution: Class Interval Frequency 100-under 200 25 200-under 300 45 300-under 400 30 What is the cumulative frequency of the second class interval?

70

A person has decided to construct a frequency distribution for a set of data containing 60 numbers. The lowest number is 23 and the highest number is 68. If 5 classes are used, the class width should be approximately _______.

9

The numbers of hours worked (per week) by 400 statistics students are shown below. Number of hours Frequency 0 - 9 20 10 - 19 80 20 - 29 200 30 - 39 100 ​ The percentage of students who work at least 10 hours per week is

95%.

If the individual class frequency is divided by the total frequency, the result is the median frequency.

False

One rule that must always be followed in constructing frequency distributions is that the adjacent classes must overlap.

False

Suppose a market survey of 200 consumers was conducted to determine the likelihood of each consumer purchasing a new computer next year. The data were collected based on the age of the consumer and are shown below: Age bracket Intent to Purchase <25 54 25-34 57 35-44 49 45-54 29 >55 11 Total Surveyed 200 Using the table above, which of the following statements is true?

Individuals between 25 and 34 are most likely to purchase a new computer next year.

The following class intervals for a frequency distribution were developed to provide information regarding the starting salaries for students graduating from a particular school: Salary ($1,000s) 28-under 31 31-under 35 34-under 37 39-under 40 Before data was collected, someone questioned the validity of this arrangement. Which of the following represents a problem with this set of intervals?

Some numbers between 28,000 and 40,000 would fall into two different intervals.

A summary of data in which raw data are grouped into different intervals and the number of items in each group is listed is called a frequency distribution.

True

In a cumulative relative frequency distribution, the last class will have a cumulative relative frequency equal to

one.

The sum of the relative frequencies for all classes will always equal

one.

A tabular summary of a set of data showing the fraction of the total number of items in several classes is a

relative frequency distribution.

In a cumulative frequency distribution, the last class will always have a cumulative frequency equal to

the total number of elements in the data set.