# EBook Problems EDA Pics

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## EBook Problems Set - Pictures of Data Problems

### Problem 1

Two random samples were taken to determine backpack load difference between seniors and freshmen, in pounds. The following are the summaries:

 Year Mean SD Median Min Max Range Count Freshmen 20.43 4.21 17.20 5.78 31.68 25.9 115 Senior 18.67 3.56 18.67 5.31 27.66 22.35 157

Which of the following plots would be the most useful in comparing the two sets of backpack weights?

(a) Histograms
(b) Dot Plots
(c) Scatter Plots
(d) Box Plots

### Problem 2

School administrators are interested in examining the relationship between height and GPA. What type of plot should they use to display this relationship?

(a) box plot
(b) scatter plot
(c) line plot
(d) dot plot

### Problem 3

What would be the most appropriate plot for comparing the heights of the 8th graders from different ethnic backgrounds?

(a) bar charts
(b) side by side boxplot
(c) histograms
(d) pie charts

### Problem 4

Your local running club has its own track and keeps accurate records of each member's age and individual best lap time around the track so members can make comparisons with their peers. The club publishes the histogram for age of the members and another histogram for their running times (the histograms are not shown here). These histograms are very symmetric, almost bell shaped. Suppose you wanted to show a group of new members how much joining this team improves people's running times. Are the two histograms published by the club useful to show this?

(a) Yes, the time one because it shows the time
(b) No, because they are not comparing times for those who are not in the club and time for those who are in the club
(c) No sets of histograms could show this point
(d) Yes, the age one, because it shows that there are people of all ages in this club

### Problem 5

There is a compay in which a very small minority of males (3%) receive three times the median salary of males, and a very small minority of females (3%) receive one-third of the median salary of females. What do you expect the side-by-side boxplot of male and female salaries to look like?

(a) Both boxplots will be skewed and the median line will not be in the middle of any of the boxes.
(b) Both boxplots will be skewed, in the case of the females the median line will be close to the top of the box and in the case of the males the median line will be closer to the bottom of the box.
(c) Need to have the actual data to compare the shape of the boxplots.
(d) Both boxplots will be skewed, in the case of males the median line will be close to the top of the box and for the females the median line will be closer to the bottom of the box.

### Problem 6

A school principal wants to examine the effect of an after-school program on improving the students' math skills. Two groups of students participated in the after-school program: the students who received F's or D's in math, and the students who received C's in math. There are 100 students in each group. Both groups of students are given the same math test before and after the program. Results show that the students who had F's and D's showed more improvement than those who had C's. What do you expect the histogram of the net scores for these two groups to look like? (net = after score - before score)

(a) Symmetrical
(b) Skewed to the left
(c) Bimodal
(d) Skewed to the right

### Problem 7

If you have the boxplot and the ogive for the weight of 200 newborn babies, how can you find the five number summary?

(a) We need the actual data
(b) By using the ogive
(c) By using either the ogive or the boxplot
(d) By using the boxplot

### Problem 8

A researcher has collected the following information on a random sample of 200 adults in the 40-50 age range:

Weight in pounds Heart beats per minute Smoker or non-smoker Single or married

He wants to examine the relationship between: 1) heart beat per minute and weight, and 2) smoking and marital status.

(a) He should draw a scatter plot of heart beat and weight, and a segmented bar chart of smoking and marital status.
(b) He should draw a side by side boxplot of heart beat and weight and a scatterplot of smoking and marital status.
(c) He should draw a side by side boxplot of smoking and marital status and a segmented bar chart of hear beat and weight.
(d) He should draw a back to back stem and leaf plot of weight and heart beat and examine the cell frequencies in the contingency table for smoking by marital status.

### Problem 9

John is enrolled in a science course that has one hundred students. In the midterm exam 95 students have scores between 60 to 80 and five students score between 95 to 98. If you make a plot of this data, what do you expect it to look like?

(a) positively skewed
(b) negatively skewed
(c) need to make a log transformation to make it smooth
(d) bimodal

### Problem 10

What do you expect the distribution of income in third world countries, where more than 50% of people are poor, to look like?

(a) Need more data to determine shape of the distribution
(b) Unimodal and skewed to the right
(c) Bimodal
(d) Unimodal and skewed to the left

### Problem 11

What kinds of variables are used to make side-by-side boxplots?

(a) Categorical only
(b) Varies according to situation
(c) One categorical and one quantitative
(d) Quantitative only

### Problem 12

After you use the five-number summary {20,35,45,50,60} to construct a boxplot for a distribution of scores on a vocabulary test, determine which of the following statements about the distribution that CANNOT be justified.

(a) About 75% of the scores are equal to or above 35.
(b) The range is 40.
(c) There are more scores from 35 to 45 than scores from 45 to 50.
(d) The distribution is skewed to the left or low end.
(e) The interquartile range is 15

### Problem 13

A set of scores from a vocabulary test given to a large group of international students can be summarized with this five-number summary: {20,35,45,50,60} Determine which of the following statements about the distribution CANNOT be justified.

(a) There are more scores from 35 to 45 than scores from 45 to 50
(b) About 75% of the scores are equal to or above 35
(c) The interquartile range is 15
(d) The range is 40
(e) The distribution is skewed to the left or low end

### Problem 14

As part of an experiment in perception, 160 UCLA psych students completed a task on identifying similar objects. On average, the students spent 8.25 minutes with standard deviation of 2.4 minutes. However, the minimum time was 2.3 minutes and one students worked for almost 60 minutes. What is the best description of the histogram of times that students spent on this task?

(a) The histogram of times could be symmetrical and not normal with major outliers.
(b) The histogram of times could be left skewed, and in case there are any outliers, it is likely that they will be smaller than the mean.
(c) The histogram of times could be right skewed, and in the case of any outliers, it is likely that they will be larger than the mean.
(d) The histogram of times could be normal with no major outliers.