Section 2.1 to 2.3 Homework

The __________ is the difference between consecutive lower class limits.

Class width

A phlebotomist draws the blood of a random sample of 50 patients and determines their blood types as shown. Construct a frequency distribution. Construct a relative frequency distribution. According to the data, which blood type is most common? According to the data, which blood type is least common? Use results of the sample to conjecture the percentage of the population that has O blood type. Is this an example of descriptive or inferential statistics? Contact a local hospital and ask them the percentage of the population that is blood type O. Why might the results differ?

A: 15 AB: 3 B: 7 O: 25 A: 0.3 AB: 0.06 B: 0.14 O: 0.5 O AB 50%; inferential The results might differ because there is always variability because the individuals in a survey may not exactly reflect the makeup of the population.

An airline offers discounted flights from Atlanta to five American cities. Below is a frequency distribution of the number of tickets purchased for each location based on a random sample of purchased tickets. Construct a relative frequency distribution of the data. What proportion of the tickets were for New York? A local news broadcast reported 7.3% of tickets purchased form the airline are for flights to San Diego. What is wrong with this statement?

LV: 0.257 O: 0.286 NY: 0.231 C: 0.153 SD: 0.073 0.231 No level of confidence is provided along with the estimate.

The ________ class limit is the smallest value within the class and the _______ class limit is the largest value within the class.

Lower. Upper.

The pie chart below depicts the beverage size customers choose while at a fast food restaurant. What is the most popular size? What percentage of customers choose this size? What is the least popular size? What percentage of customers choose this size? What percent of customers choose a small-sized beverage?

Medium; 60% Large; 6% 13%

A newspaper article claimed that the afternoon hours were the worst in terms of robberies and provided the graph to the right in support of this claim. Explain how this graph is misleading.

Not all of the time intervals are the same size. Redistributing the time interval so they are all the same size may lead to a different shape.

A frequency distribution lists the _________ of occurrences of each category of data, while a relative frequency distribution lists the __________ of occurrences of each category of data.

Number, proportion.

The following data represent the number of grams of fat in breakfast meals offered at a local fast food restaurant. ​(a) Construct an ordered​ stem-and-leaf plot and ​(b) describe the shape of the distribution. (a): Construct the ordered stem and leaf plot. (b): The distribution is _______.

(a): 0 : 4 5 5 8 8 1 : 1 2 2 3 5 7 8 9 2 : 0 0 4 5 9 3 : 5 7 9 4 : 0 (b): skewed right

Determine the original set of data. 1 : 0 1 7 2 : 1 4 4 7 9 3 : 3 5 5 5 7 8 4 : 0 1

10, 11, 17, 21, 24, 24, 27, 29, 33, 35, 35, 35, 37, 38, 40, 41

What is a bar graph? What is a Pareto chart?

A bar graph is a horizontal or vertical representation of the frequency or relative frequency of the categories. The height of each rectangle represents the category's frequency or relative frequency. A Pareto chart is a bar graph whose bars are drawn in decreasing order of frequency or relative frequency.

The following frequency histogram represents the IQ scores of a random sample of​ seventh-grade students. IQs are measured to the nearest whole number. The frequency of each class is labeled above each rectangle. How many students were sampled? Determine the class width. Identify the classes and their frequencies. Which class has the highest frequency? Which class has the lowest frequency? What percent of students had an IQ of at least 120? Did any students have an IQ of 164?

200 students The class width is 10 60-69, 1​; 70-79, 2​; 80-89, 11; 90-99, 41​; 100-109,56​; 110-119, 43​; 120-129, 33; ​130-139, 7​; 140-149, 4​; 150-159, 2. 100 - 109 60 - 69 23% No, because there are no bars, or frequencies, greater than an IQ of 160.

Suppose a survey of adults and teens (ages 12-17) in a certain country was conducted to determine the number of texts sent in a single day. Construct a relative frequency distribution for adults. Construct a relative frequency distribution for teens. Compare the texting habits of adults and teens.

Adults: 0.094, 0.504, 0.128, 0.131, 0.067, 0.077 Teens: 0.020, 0.222, 0.101, 0.186, 0.189, 0.281 Adults are more likely to send few texts per day, while teens are more likely to send many texts per day.

_________ are the categories by which data are grouped.

Classes

The shape of the distribution shown is best classified as skewed left.

False

The shape of the distribution shown is best classified as uniform.

False

The following Pareto chart shows the position played by the most valuable player (MVP) in a certain baseball league for the last 87 years. Which position had the most MVPs? How many MVPs played catcher (C)? How many more MVPs played outfield (OF) than catcher? There are three outfield positions (left field, center field, right field). Given this, how might the graph be misleading?

Outfield (OF). 8 MVPs played catcher. 25 more MVPs played outfield than catcher. The chart seems to show that one position has many more MVPs because three positions are combined into one. They should be separated.

For a number of children in a family, state whether you would expect a histogram of the data to be bell-shaped, uniform, skewed left, or skewed right.

Skewed right

The data to the right represent the top speed​ (in kilometers per​ hour) of all the players​ (except goaltenders) in a certain soccer league. Find ​(a) the number of​ classes, ​(b) the class limits for the third class, and ​(c) the class width. (a): There are ____ classes. (b): The lower class limit for the third class is _____. The upper class limit for the third class is _____. (c): The class width is _____.

(a): 6 (b): 18, 21.9 (c): 4

The graph to the right represents the expenditures of a company. (a): How is the graph misleading? (b): What could be done to improve the graphic?

(a): It looks like twice as much money is spent on wages than products. (b): The lengths of the bars should be proportional to the percentages.

The following graph shows the median earnings for females from 2005 to 2009 in constant 2009 dollars. (a): How is the bar graph misleading? What does the graph seem to convey? (b): What does the new graph seem to convey?

(a): The vertical axis starts at​ 34,500 instead of 0. This tends to indicate that the median earnings for females changed at a faster rate than it actually did. (b): This graph indicates that median earnings for females have remained fairly constant over the given time period.