Chp 2 Quiz STA 2023 McGraw Hill

When constructing a scatterplot for two quantitative variables, we usually refer to one variable as x and another one as y. Typically, we graph x on the vertical axis and y on the horizontal axis.

False When constructing a scatterplot for two quantitative variables, we usually refer to one variable as x and another one as y. Typically, we graph x on the horizontal axis and y on the vertical axis.

A polygon connects a series of neighboring points where each point represents the midpoint of a particular class and its associated frequency or relative frequency.

True Polygons are graphical depiction of frequency and relative frequency distributions. It connects a series of neighboring points where each point represents the midpoint of a particular class and its associated frequency or relative frequency.

A car dealership created a scatterplot showing the manufacturer's retail price and profit margin for the cars they have on their lot. Picture As the manufacturer's suggested retail price increases, the profit margin tends to ___________.

increase The graph shows that the higher the MSRP, the higher the profit margin.

In the accompanying stem-and-leaf diagram, the values in the stem-and-leaf portions represent 10s and 1s digits, respectively. Picture The stem-and-leaf diagram shows that the distribution is ___________.

positvely skewed

What type of relationship is indicated in the scatterplot? Picture

postive curvilinear relationship

In the accompanying stem-and-leaf diagram, the values in the stem and leaf portions represent 10s and 1s digits, respectively. Picture Which of the following numbers appears in the stem-and-leaf diagram?

38

Consider the following frequency distribution. Class Frequency 12 up to 15 3 15 up to 18 6 18 up to 21 3 21 up to 24 4 24 up to 27 4 What proportion of the observations are at least 15 but less than 18?

0.3 Six observations of the 20 total observations fall in the class of 15 up to 18: 6/20 = 0.30.

How does an ogive differ from a polygon?

An ogive is a graphical depiction of a cumulative frequency or cumulative relative frequency distribution, while a polygon is a graphical depiction of a frequency or relative frequency distribution.

Which of the following best describes a frequency distribution for qualitative data?

It groups data into categories and records the number of observations in each category.

The following histogram represents the number of pages in each book within a collection. What is the frequency of books containing at least 250 but fewer than 300 pages?

7 Use frequencies shown on the histogram for different number of pages in the book.

The following is a list of five of the world's busiest airports by passenger traffic for 2010. Name Location # of Passengers (in millions) Hartsfield-Jackson Atlanta, Georgia, United States 89 Capital International Beijing, China 74 London Heathrow London, United Kingdom 67 O'Hare Chicago, Illinois, United States 66 Tokyo Tokyo, Japan 64 The percentage of passenger traffic in the five busiest airports that occurred in Asia is the closest to ___________.

38%

Use the following data to construct a scatterplot. What type of relationship is implied? x 3 6 10 14 18 23 y 34 28 20 12 5 0

A negative relationship

The following data represent the recent sales price (in $1,000s) of 24 homes in a Midwestern city. 187 125 165 170 230 139 195 229 239 135 188 210 228 172 127 139 122 181 196 237 115 199 170 239 picture Click here for the Excel Data File Suppose the data on house prices will be grouped into five classes. The width of the classes for a frequency distribution or histogram is the closest to _______.

25 Width of class = (max value − min value)/(# of classes) Width = (239 − 115)/5 = 24.8; so round up to 25.

Students in Professor Smith's business statistics course have evaluated the overall effectiveness of the professor's instruction on a five-point scale, where a score of 1 indicates very poor performance and a score of 5 indicates outstanding performance. The raw scores are displayed in the accompanying table: 1 4 4 5 5 3 4 3 4 1 5 5 4 4 2 3 3 2 3 3 4 5 5 5 5 3 2 3 3 2 picture Click here for the Excel Data File What is the most common score given in the evaluations?

3

The following data represent scores on a pop quiz in a statistics section: 45 66 74 72 62 44 55 70 33 82 56 56 84 16 16 47 32 32 17 37 picture Click here for the Excel Data File Suppose the data are grouped into five classes, and one of them will be "30 up to 44." that is, {x; 30 ≤ x < 44}. The frequency of this class is _____.

4 There are four data values that are at least 30 but less than 44. They are 32, 32, 33, and 37.

Students in Professor Smith's business statistics course have evaluated the overall effectiveness of the professor's instruction on a five-point scale, where a score of 1 indicates very poor performance and a score of 5 indicates outstanding performance. The raw scores are displayed in the accompanying table: 1 4 4 5 5 3 4 3 4 1 5 5 4 4 2 3 3 2 3 3 4 5 5 5 5 3 2 3 3 2 picture Click here for the Excel Data File What is the relative frequency of the students who gave Professor Smith an evaluation of 3?

0.3 Nine of the 30 students gave Professor Smith a 3. The relative frequency is thus 9/30 = 0.3.

The accompanying relative frequency distribution represents the last year car sales for the sales force at Kelly's Mega Used Car Center. Car Sales Relative Frequency 35 up to 45 0.07 45 up to 55 0.15 55 up to 65 0.31 65 up to 75 0.22 75 up to 85 0.25 If Kelly's employs 100 salespeople, how many of these salespeople have sold at least 45 but fewer than 65 cars in the last year?

46 (0.15 + 0.31)100 = 46 employees.

The following stem-and-leaf diagram shows the speeds in miles per hour (mph) of 14 cars approaching a toll booth on a bridge in Oakland, California. Picture How many of the cars were traveling faster than 25 mph but slower than 40 mph?

9

When summarizing quantitative data it is always better to have up to 30 classes in a frequency distribution.

False It depends on the size of the data set. The recommended number of classes usually ranges from 5 to 20.

A stem-and-leaf diagram is constructed by separating each value of a data set into two parts. What are these parts?

Stem consisting of the leftmost digits and leaf consisting of the last digit