Statistics Chapter 3
Gas prices in a metropolitan area range from $2.75 to $3.18, with an average of $2.93. Use the range rule of thumb to estimate the standard deviation.
$0.108
The following data represent the total price, in dollars, of 20 randomly-selected gasoline purchases at a certain convenience store. Find the mean price for these purchases.
$36.82
The following data represent the total price, in dollars, of 20 randomly-selected gasoline purchases at a certain convenience store. Find the median price for these purchases.
$39.95
Following are the closing prices (in dollars) of a certain stock for the past 20 trading days.Find the population standard deviation for the closing prices.
$9.14
If a student scored 77 points on a test where the mean score was 84.5 and the standard deviation was 5.1. The student's z score is
-1.47
A population has a mean and standard deviation Find the z-score for a population value of 29.
-1.7
A data set has a mean of 162 and a standard deviation of 11. Compute the coefficient of variation.
0.07
According to Chebyshev's theorem, the maximum proportion of data values from a data set that are more than 1.5 standard deviations from the mean is
0.44
Given that the variance for a data set is , what is the standard deviation?
1.10
A baseball player has a batting average of each week of the season, with a standard deviation of . What is the z score when he bats one week?
1.308
Gina and Stewart are surf-fishing on the Atlantic coast, where both bluefish and pompano are common catches. The mean length of a bluefish is 276 millimeters with a standard deviation of For pompano, the mean is with a standard deviation of Stewart caught a bluefish that was long. What was the z-score for this length?
1.33
Find the mode for the following data set: 18 22 10 16 10
10
Find the mean of the following data set.9, 11, 11, 11, 9, 15
11.0
If a set of data has mean 36 and variance 16, then its coefficient of variation is
11.1%
Given that the mean of a set of data is 25 and the standard deviation is 3, what is the coefficient of variation?
12%
Find the mean of the following set of values.8, 15, 13, 11, 13
12.0
For the data set below, find the outlier(s).
123 and 201
The table below lists the populations, in thousands, of several rural western counties. What is the mean population?
14.8 thousand
Find the mean for the following data set: 21 23 12 15 13
16.8
Find the mode for the following data set: 17 28 10 32 23 17
17
What is the median of the following set of values?7, 21, 19, 15, 19, 14, 15, 19
17
The grades for the trigonometry exam are listed below. Find the range. 85, 76, 93, 82, 90, 75
18
Approximate the sample variance given the following frequency distribution.
182.3
Find the median for the following data set: 27 21 18 30 13 13
19.5
A student received the following grades last semester. Find the student's semester grade point average.
2.13
Find the mode for the following data set: 22 32 14 34 26 22
22
The table below lists the populations, in thousands, of several rural western counties. What is the median population?
22 thousand
For the data set below, find the upper outlier boundary.
221
For the data set below, find the 15th percentile.
24.5
The height of basketball players on a high-school team averages 79.1 inches, with the shortest player being 71 inches tall, and the tallest 85 inches tall. Use the range rule of thumb to estimate the standard deviation of the height.
3.5 inches
A recent survey of a new diet cola reported the following percentages of people who liked the taste. Find the weighted mean of the percentages.
32
The average weekly earnings in dollars for various industries are listed below. Find the percentile rank of 634. 737, 634, 569, 671, 597, 701, 766, 542, 788, 819
35th
The following table presents the heights (in inches) of a sample of college basketball players. Considering the data to be a population, approximate the standard deviation of the heights.
4.2
Use the boxplot to identify the maximum value, minimum value, median, first quartile, third quartile, and interquartile range.
500, 350, 450, 400, 475, 75
Find the population variance for the following data set: 16 21 30 27 37
52.6
Find the sample variance for the following data set: 15 22 29 28 35
57.7
Find the median of the following data set.3, 10, 7, 6, 3
6
What is the median of the following set of values?8, 6, 3, 1, 12
6
Following are heights, in inches, for a sample of college basketball players. Find the sample standard deviation for the heights of the basketball players.
6.2
A student has an average of 78 on seven chapter tests. If the student's scores on six of the tests are 76, 74, 76, 80, 83, and 91, what was the score on the remaining test?
66
For the data set below, list the outliers, if any.
7 and 92
Approximate the sample standard deviation given the following frequency distribution.
7.5
Check the following data set for outliers.73, 82, 84, 84, 86, 87, 89, 91
73 is an outlier
Find the weighted mean for a particular student's scores on three exams if the first one was worth 75 points and the student received a score of , the second was worth 50 points and the student received a score of , and the third was worth 30 points and the student received a score of ?
78.1
The costs per load (in cents) of 26 detergents tested by a consumer organization are shown here. Find the standard deviation of the sample.
8.5
If a data set has 25 values and a standard deviation 9.4, then the variance is
88.4
A soft-drink bottling company fills and ships soda in plastic bottles with a target volume of 354 milliliters. The filling machinery does not deliver a perfectly consistent volume of liquid to each bottle, and the three quartiles for the fill volume are and Find the IQR.
9
Which of the following is the properly rounded mean for the given data?7, 8, 13, 9, 10, 11
9.7
A data set has a mean of 50 and a standard deviation of 10. Which of the following might possibly be true?
At least 89% of the data values are between 20 and 80.
Using the table below, what grade would a student who ranked in the percentile receive.
C
Which of the following is true?
D5 = P50 = Q2
The data below show the amount of medical-marijuana sales tax paid in Denver County, Colorado. Find the first and third quartiles for the data.
Q1 = 353,251; Q3 = 513,167.5
The number of incidents in which police were needed for a sample of 9 schools in Allegheny County is 8, 39, 6, 12, 45, 16, 3, 0, 15. Find the first and third quartiles for the data.
Q1 = 4.5; Q3 = 27.5
Gina and Stewart are surf-fishing on the Atlantic coast, where both bluefish and pompano are common catches. The mean length of a bluefish is 282 millimeters with a standard deviation of For pompano, the mean is with a standard deviation of Stewart caught a bluefish that was long, and Gina caught a pompano that was long. Who caught the longer fish, relative to fish of the same species?
Stewart
Which plot below has a five-number summary of 5, 6, 7, 9, 12 and an interquartile range of 3?
between 6 and 9 / 5-12
The coefficient of variation for a data set is the mean divided by the standard deviation, expressed as a percentage.
false
The interquartile range is found by subtracting the mean from the maximum value of a data set.
false
The variance of a data set is the square root of the standard deviation.
false
The size of the box in a boxplot shows the of the data set.
interquartile range
For the data shown in the histogram, which of the following choices best describes the relationship between the median and the mean?
median ≈ mean
The is the mode for grouped data.
modal class
A data set contains three unique values. Which of the following must be true?
none of these
are either extremely high or extremely low data values compared with the rest of the data.
outliers
A report states that the mean household income last year for a certain rural county was $44,100 and the median was $35,300. If a histogram were constructed for the incomes of all households in the county, would you expect it to be skewed to the right, to the left, or approximately symmetric?
skewed right
In a unimodal, symmetrical distribution as shown in the figure below,
the mean, the median, and the mode are the same.
Chebyshev's theorem can be used to find the minimum percentage of the values in a data set that will fall within a certain distance of the mean.
true
The median can be a more appropriate measure of central tendency if the distribution of the data is extremely skewed.
true
The following data represent the ice cream flavor choices of 20 diners at a college cafeteria. Which flavor ice cream is the mode?
vanilla