# Standard Deviation Assignment And Quiz 90%

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question
Which of the distributions is left skewed?
a
question
Cara computes the mean and variance for the set 87, 46, 90, 78, and 89. She finds the mean to be 78. Her steps for finding the variance are shown below. What is the first error Cara made in computing the variance?
She put the negative sign for the 32 outside the parentheses.
question
Adimas found the mean of her 11 math test scores for the first semester. x = StartFraction (76 + 87 + 65 + 88 + 67 + 84 + 77 + 82 + 91 + 85 + 90) Over 11 EndFraction = StartFraction 892 Over 11 EndFraction ≈ 81 Using 81 as the mean, find the variance of her grades rounded to the nearest hundredth. σ2 = Find the standard deviation of her grades rounded to the nearest hundredth. σ =
71.36 8.45
question
Henry recorded the number of miles he biked each day for a week. His miles were 25, 40, 35, 25, 40, 60, and 75. Enter the data into the statistics calculator. What is the standard deviation of the miles Henry biked to the nearest tenth?
17.1
question
Enter each data set into the statistics calculator. Make note of the mean, median, and shape of the histogram of each data set. A = {10, 12, 12, 6, 8, 5, 4, 10, 8, 10, 12, 12, 6} B = {8, 8, 8, 7, 9, 7, 9, 10, 6, 8} Which statements are true about the data sets? Check all that apply. Set A is symmetrical. Set B has the same mean and median. Set B is right skewed. Set A is left skewed. The median of set A is larger than the mean of set A.
Set B has the same mean and median. Set A is left skewed. The median of set A is larger than the mean of set A.
question
Consider the normal distribution curve. Which statements are true about the curve? Check all that apply. The standard deviation of the data is 64. The variance of the data is 49. The median is 64. The data point 75 is less than one standard deviation from the mean. The data point 50 is two standard deviations away from the mean.
The variance of the data is 49. The median is 64. The data point 50 is two standard deviations away from the mean.
question
The mean tests scores with standard deviations of four English classes are given in the table. Which statement is most likely to be true? The scores from Mrs. Jones's class are the closest to the class mean. The scores from Mrs. Rijo's class are the closest to the class mean. The scores from Mr. Phan's class are the closest to the class mean. The scores from Mrs. Scott's class are the closest to the class mean.
The scores from Mrs. Rijo's class are the closest to the class mean.
question
A normal distribution curve, where x = 70 and σ = 15, was created by a teacher using her students' grades. What information about their performances can be obtained by analyzing the curve?
By analyzing the curve, you can tell that the average, or mean, grade is 70. This is also the median of the grades, so we know that one half of the scores are less than or equal to 70, and the other half of the scores are greater than or equal to 70. The bulk of the scores are between 55 and 85.
question
The graph shows a distribution of data. What is the variance of the data? 0.0625 0.25 0.5 1.5
NOT: 0.25
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The histogram shows a city's daily high temperatures recorded for four weeks. Which phrase describes the shape of the temperature data? symmetrical left-skewed right-skewed normal
left-skewed
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The graph shows a distribution of data. A graph shows the horizontal axis numbered 1 to x. The vertical axis is unnumbered. The graph shows an upward trend from 1 to 2 then a downward trend from 2 to 3. What is the standard deviation of the data? 0.5 1.5 2.0 2.5
0.5
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Which histogram represents a set of data that is left-skewed?
c
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The graph represents the distribution of the lengths of play times, in minutes, for songs played by a radio station over one hour. A graph shows the horizontal axis numbered 2.6 to x. The vertical axis is unnumbered. The graph shows an upward trend from 2.8 to 3.4 then a downward trend from 3.4 to 4. Which statement is true about the songs played during the one-hour interval? Most of the songs were between 3 minutes and 3.8 minutes long. Most of the songs were 3.4 minutes long. Most of the songs were less than 3.2 minutes long. Most of the songs were more than 3.6 minutes long.
Most of the songs were between 3 minutes and 3.8 minutes long.
question
Grace is looking at a report of her monthly cell-phone usage for the last year to determine if she needs to upgrade her plan. The list represents the approximate number of megabytes of data Grace used each month. 700, 735, 680, 890, 755, 740, 670, 785, 805, 1050, 820, 750 What is the standard deviation of the data? Round to the nearest whole number. 65 75 100 130
100
question
The mean shoe size of the students in a math class is 7.5. Most of the shoe sizes fall within 1 standard deviation, or between a size 6 and a size 9. What is the standard deviation of the shoe size data for the math class? 1.5 2.7 3.0 3.8