Stats Unit 1 Test

Twenty students in Class A and 20 students in Class B were asked how many hours they took to prepare for an exam. The data sets represent their answers. Class A: {2, 5, 7, 6, 4, 3, 8, 7, 4, 5, 7, 6, 3, 5, 4, 2, 4, 6, 3, 5} Class B: {3, 7, 6, 4, 3, 2, 4, 5, 6, 7, 2, 2, 2, 3, 4, 5, 2, 2, 5, 6} Which statement is true for the data sets? A. The mean study time of students in Class A is less than students in Class B. B. The mean study time of students in Class B is less than students in Class A. C. The median study time of students in Class B is greater than students in Class A. D. The range of study time of students in Class A is less than students in Class B. E. The mean and median study time of students in Class A and Class B is equal.

B. The mean study time of students in Class B is less than students in Class A.

Gabe is the human resources manager for the Advanced Scientific Research Lab. He has to recordthe heights (in centimeters) and weights (in pounds) for each of the scientists in the lab. Height distribution (cm): 178, 163, 174, 186, 154, 167, 167, 181, 159, 165, 177, 191, 158 Weight distribution (lbs): 157, 163, 190, 187, 183, 173, 184, 189, 193, 192, 177, 173, 168 What are the medians for the height and weight distribution, respectively? A. 170, 179 B. 183, 167 C. 167, 183 D. 179, 170 E. 165, 175

C. 167, 183

What is the mode of this data set? {41, 43, 45, 3, 11, 23, 24, 27, 29, 45, 12, 19, 22, 49, 25} A. 25 B. 27.8 C. 45 D. 46 E. 49

C. 45

Which statement is true about a dot plot? A. A dot plot shows the median of a data set. B. A dot plot shows the first quartile, but not the second quartile of any given data set. C. A dot plot shows the frequency of the individual values of any given data set. D. A dot plot shows the frequency of an interval of values of any given data set. E. A dot plot gives information about the average of any given data set.

C. A dot plot shows the frequency of the individual values of any given data set.

The spread of data set X is greater than the spread of data set Y, and the data sets are normally distributed. Which statement is true? A. The mean of data set X is greater than the mean of data set Y. B. The median of data set X is less than the median of data set Y. C. The standard deviation of data set X is greater than the standard deviation of data set Y. D. The range of data set X is less than the range of data set Y. E. The mode of data set X is greater than the mode of data set Y.

C. The standard deviation of data set X is greater than the standard deviation of data set Y.

The grades received by 200 students follow a normal distribution. The mean of the grades is 70%, and the standard deviation is 7%. The number of students who received a grade greater than 70% is about _____(1), and the number of students who got a grade higher than 84% is about _______(2).

(1) 100 (2) 5

James needs to clock a minimum of 9 hours per day at work. The data set records his daily work hours, which vary between 9 hours and 12 hours, for a certain number of days. {9, 9.5, 10, 10.5, 10.5, 11, 11, 11.5, 11.5, 11.5, 12, 12}. The median number of hours James worked is ___(1). The skew of the distribution is ____(2) with symmetry.

(1) 11 (2) negative

Type the correct answer in each box. Spell all words correctly, and use numerals instead of words for numbers. If necessary, use / for the fraction bar(s). The data set gives the number of bottles filled by each of the workers in a bottling plant in one day. {36, 18, 16, 28, 68, 35, 37, 66, 38, 40, 41, 44, 72, 29} The best measure of center for this data set is the ____(1), and its value expressed up to one decimal place is ____(2).

(1) median (2) 37.5

The mean midday temperature recorded in June in a city in South California is 36ºC, and the standard deviation is 3ºC. The number of days in the month of June is 30. Assuming the data is normally distributed, the number of days in June when the midday temperature was between 39ºC and 42ºC is ____.

4

A survey was conducted at Springdale High to find the number of hours students sleep at night. The histogram shows the data collected in this survey. Which statement about the number of hours students sleep is true? (2-4 hours: 2, 4-6 hours: 10, 6-8 hours: 17, 8-10 hours: 9) A. Seventeen students sleep between 6 and 8 hours at night. B. Seventeen students sleep for 6 hours at night. C. Ten students sleep for 4 hours at night. D. Six students sleep between 2 and 4 hours at night. E. Four students sleep for 10 hours at night.

A. Seventeen students sleep between 6 and 8 hours at night.

The second quartile of a data set is 4.2. Which statement about the data values is true? A. The data value 2.5 will lie below the second quartile. B. The data value 4.7 will lie below the second quartile. C. One fourth of the values are less than or equal to 4.2, and three fourths are above 4.2. D. One fourth of the values are less than or equal to 4.2, and half of the values are above 4.2. E. One fourth of the values are above 4.2, and half of the values are less than or equal to 4.2.

A. The data value 2.5 will lie below the second quartile.

Which statement is true? A. The mean lies to the right of the median for a positively skewed distribution. B. The mean lies to the left of the median for a positively skewed distribution. C. The mean lies to the left of the median for a symmetric distribution. D. A distribution skewed to the right is said to be negatively skewed. E. A distribution skewed to the left is said to be positively skewed.

A. The mean lies to the right of the median for a positively skewed distribution. dunno tho

What is the shape of the following distribution? {9, 10, 10, 11, 11, 12, 12, 13, 13, 13, 14, 14, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 17, 17, 17, 17, 18, 19, 20} A. negative skew B. positive skew C. symmetric D. asymmetric with no skew E. none of the above

A. negative skew

Which statement holds true for a skewed histogram showing a distribution of the weights of students in a class? A. The number of weights on the right side of the mode is equal to the number of weights on the left. B. The number of weights on the left side of the mean is equal to the number of weights on the right. C. The mean weight and the median weight will be the same for the distribution. D. The nature of the skew can be verified by the position of the mean with respect to the median. E. The nature of the skew can be verified by the position of the mean with respect to the mode.

D. The nature of the skew can be verified by the position of the mean with respect to the median.

Which data set is the farthest from a normal distribution? A. 2, 3, 3, 4, 4, 4, 5, 5, 6 B. 3, 4, 5, 6, 6, 7, 7, 7, 8, 8, 9, 10 - 7 C. 0.9, 1.0, 1.0, 1.1, 1.1, 1.1, 1.2, 1.2, 1.3 D. 4, 4, 4, 5, 5, 6, 7, 7, 8, 8, 8 E. 2, 4, 5, 5, 6, 6, 7, 7, 7, 8, 8, 9, 9, 10

D.4, 4, 4, 5, 5, 6, 7, 7, 8, 8, 8

Assume that the numbers of a data set are arranged in ascending order. Which statement about the third quartile is true? A. All of the numbers lie below the third quartile. B. All of the numbers lie above the third quartile. C. 50% of the numbers lie below or on the third quartile, and the remaining 50% lie above it. D. 25% of the numbers lie below or on the third quartile, and the remaining 75% lie above it. E. 75% of the numbers lie below or on the third quartile, and the remaining 25% lie on or above it.

E. 75% of the numbers lie below or on the third quartile, and the remaining 25% lie on or above it.

Gabe is the human resources manager for the Advanced Scientific Research Lab. He has to recordthe heights (in centimeters) and weights (in pounds) for each of the scientists in the lab. Height distribution (cm): 178, 163, 174, 186, 154, 167, 167, 181, 159, 165, 177, 191, 158 Weight distribution (lbs): 157, 163, 190, 187, 183, 173, 184, 189, 193, 192, 177, 173, 168 What is the shape of the height and weight distribution? A. The height and weight distribution exhibit a negative and a positive skew, respectively. B. Both the height and weight distribution exhibit a positive skew. C. Both the height and weight distribution exhibit a negative skew. D. Both the height and weight distribution are symmetric about the mean. E. The height and weight distribution exhibit a positive and a negative skew, respectively.

E. The height and weight distribution exhibit a positive and a negative skew, respectively.

Find the range and the interquartile range of the data set represented by the box plot. (min: 4, 1st: 5.5, 2nd: 11, 3rd: 15.5, max: 18)

range: 14 IQR: 10

What is the first quartile and median of the box plot (min: 8, 1st: 12, 2nd: 16, 3rd: 19, max: 24)

1st: 12 median/2nd: 16

The number of books borrowed from a library each week follows a normal distribution. When a sample is taken for several weeks, the mean is found to be 190 and the standard deviation is 30. There is a ____ chance that more than 250 books were borrowed in a week.

2.5 %