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Which of the following statements about a normal distribution is true?
A large portion of the data is skewed to the right.
A large portion of the data is located near the tails.
The normal distribution is an example of a bimodal distribution.
The normal distribution is single-peaked and symmetric. 2 The manager went over the sales of mobile phones at the store and found that the mean sale was 45, with a standard deviation of 4. On a particular day, 52 mobile phones were sold. What is the z-score of the sale of mobile phones on that day?
28
The dotplot below shows the number of text messages received by a group of students in a day
How many students received less than 15 messages?
20
4
15
9 4 Which of the following statements is true?
According to the Central Limit Theorem, the mean of the sampling distribution is equal to the population mean as long as the sample size is large enough.
According to the Central Limit Theorem, the mean of the sampling distribution is greater than the population mean.
According to the Central Limit Theorem, the mean of the sampling distribution is equal to the standard deviation.
According to the Central Limit Theorem, the mean of the sampling distribution is greater than the standard deviation. 5
The interquartile range (IQR) is the average value of a data set.
The interquartile range (IQR) is the middle value of a data set.
The interquartile range (IQR) is influenced by outliers. 8
Sara wonders what percentage of her students answered at least half of the quiz questions incorrectly.
The relative cumulative frequency of students who earned a score of 20 or lower on the quiz is.
14%
68%
34%
Which of the following statements about the stack plot is true?
There were more male students than female students in the age group 19 -
There were more male students in the age group 19 - 20 than in the age group 15 - 16.
There were more female students in the age group 17 - 18 than in any other age group.
What is the difference in the number of students with the most and least numbers of pets?
The percent-change graph in the figure shows the change in Gross Domestic Product (GDP) from 2008-
Which segment of the graph indicates the greatest increase in GDP growth?
Let x stand for the length of an individual screw. 100 screws were sampled at a time. The population mean is 2.5 inches and the population standard deviation is 0.2 inches. What is the mean of the sampling distribution of sample means?
2
5 phones
70 phones
9 phones
10 phones 17
The third quartile (Q3) value from this box plot is.
60
37
48
29 18 For a class reading competition, the students were asked to read a book. Mike, Jack, and Rayon discussed the numbers of pages they read on the first day. One of them made a graph to represent the data.
Who made the graph, and why?
Which of the following statements about a positively skewed distribution is true?
In a survey to rate the customer service department of a company, 300 persons rated their agreement with the statement, "The staff is helpful and courteous." The information was put into a table.
c Strongly Agree 32 Agree 50 Neutral 97 Disagree 53 Strongly Disagree 68
Eight boys scored over 10 marks on the exam.
Two boys scored between 80 and 89 marks on the exam.
Twelve boys scored 8 marks on the exam.
Eight boys scored 12 marks on the exam. 23
The formula for the standard deviation of a sample is:
Select the true statement for the following data set that has a mean of 8:
Answer choices are rounded to the hundredths place.
The variance is 8.86 and the standard deviation is 2.98.
The variance is 7.50 and the standard deviation is 2.98.
The variance is 2.98 and the standard deviation is 8.86.
The variance is 8.86 and the standard deviation is 7.50.
Select the false statement about standard deviation.
It is the average of the squared differences of the values from the mean.
It is a measure of how spread out the values of a data set are.
It is the square root of variance.
It is calculated using the mean. 25
Which of the following statements is true for an outlier?
It is a data point that is below or above Q1 ± 1.5 x IQR.
It is a data point that is below or above Q3 ± 1.5 x IQR.
It is a data point that is below Q1 - 1.5 x IQR or above Q3 + 1.5 x IQR.
It is a data point that is between Q1 + 1.5 x IQR and Q3 - 1.5 x IQR. 26 In a poll of 300 preschoolers, 125 said they preferred chocolate ice cream, 71 said they preferred vanilla, 100 said they preferred cookies & cream, and 4 said they had never eaten ice cream. If a pie chart were to be made showing the preference for each flavor, the central angle for the chocolate ice cream sector would be .
41°
124°
5°
150°
