ME430 Test 1 Ch2

(T/F) The empirical rule applies to all sets of data.

False

(T/F) A data set can have more than one measure of variability.

True

(T/F) For a bell-shaped distribution, the range of the values is approximately equal to length of values within three standard deviations of the mean.

True

(T/F) In and ordered data set of numerical values, the median of the upper 50 percent of the data set corresponds to a numerical value such that 75 percent of the values are below it.

True

(T/F) Quantities that describe populations are called parameters. and quantities that describe samples are called statistics.

True

A set of exam scores are given below. Exam Scores 4| 5 6 8 5| 3 4 5 6 9 6| 2 3 5 6 6 9 9 7| 0 1 1 3 3 4 5 5 5 7 8 8| 1 2 3 6 9 9| 3 5 7 8 The mode for this data set is a) 75 b) 78 c) 45 d) 98

a) 75

What type of distribution is described by the following information? Mean = 56 Median = 58.1 Mode = 63 a) negatively skewed b) symmetrical c) bimodal d) positively skewed

a) negatively skewed

The number of minutes spent in the computer lab by 20 students working on a project are given below: Number of minutes 30| 0 2 5 5 6 6 6 8 40| 0 2 2 5 7 9 50| 0 1 3 5 60| 1 3 The median for this data set is a) 400 b) 402 c) 405 d) 407

b) 402

An instructor recorded thefollowing quiz scores ( out of a possible 10 points) for the 12 students who were present for her friday afternoon statistics class. The scores were 7, 4, 4, 7, 9, 10, 6, 7, 3, 8, 5. The mode of this set of scores is a) 9.5 b) 7 c) 6 D) 3

b) 7

The most frequently occurring value in a data set is called the a) spread b) mode c) skewness d) maximum value

b) mode

The median of a set of numerical data is the value that represents a) the middle or the approximate middle value of the data set b) the most frequently observed value in the data set c) the average of the squared deviations of the values from the mean of the data set d) the arithmetic average of the data set

a) the middle or the approximate middle value of the data set

A student has seven statistics books open in front of him. The page numbers are as follows: 231, 423, 521, 139, 347, 400, 345. the median for thisset of numbers is a) 139 b) 347 c) 346 d) 373.5

b) 347

What type of distribution could be described by the following information? Mean = 56 Median = 56.0001 Mode = 55.999 a) approcimately negatively skewed b) approximately symmetrical c) approximately positively skewed d) all of the above answers are correct

b) approximately symmetrical

Examine the following data set: 14 15 17 17 18 16 15 18 17 19 18 16 14 this data set can be appropriately characterized as a) unimodal b) bimodal c) multimodal d) all answeres are correct

b) bimodal

If the number of values in a data set is even, and the numbers are ordered from the smallest value to the largest, then a) the median cannot be found. b) the median is the average of the two middle numbers. c) the median, mode and mean are equal. d) none of the above are correct.

b) the median is the average of the two middle numbers.

Which of the following is not a measure of central tendancy? a) mode b) variability c) median d) mean

b) variability

The number of minutes spent in the computer lab by 20 students working on a project are given below: Number of minutes 30| 0 2 5 5 6 6 6 8 40| 0 2 2 5 7 9 50| 0 1 3 5 60| 1 3 The mode for this data set is a) 305 b) 402 c) 306 d) 300

c) 306

The number of minutes spent in the computer lab by 20 students working on a project are given below: Number of minutes 30| 0 2 5 5 6 6 6 8 40| 0 2 2 5 7 9 50| 0 1 3 5 60| 1 3 The mean for this data set is a) 306.0 b) 402.0 c) 403.8 d) 450.0

c) 403.8

A single numerical value is used to describe a characteristic of a sample data set, such as the sample median, is referred to as a) sample parameter b) sample median c) population parameter d) sample statistic

d) sample statistic

The mean of a set of numerical data is the value that represents a) the middle value of the data set b) the most frequently observed value c) the average of the squared deviations of the values from the mean of the data set d) the arithmetic average of the data set

d) the arithmetic average of the data set

Which of the following would be affected the most if there is an extremely large value in the data set? a) the mode b) the median c) the frequency d) the mean

d) the mean

(T/F) If the standard deviation for a data set is large, then the data set is less dispersed.

False

(T/F) Of a set of numerical data values, 50 percent will lie between one standard deviation from the mean of the data set.

False

(T/F) Of the range, the interquartile range, and the variance of a data set, the interquartile range is most influenced by outlying value in the data set.

False

(T/F) On a statistics exam, Joe's score was at the median for the lower 50 percent of the scores, and John's score was at the median of the upper 50 percent of the scores. Thus we can say that john's score was twice that of Joe's score.

False

(T/F) The empirical rule states that exactly 95 percent of a data set lie within two standard deviations of the mean.

False

(T/F) The interquartile range is the average of the medians of the lower and upper 50 percent of and ordered data set.

False

(T/F) The mean absolute deviation for a set of data always divides the data set in such a way that 50 percent of the values lie above the mean and 50 percent lie below the mean.

False

(T/F) The mean value of a data set corresponds to half the value of the range.

False

(T/F) The median is a measure of variability.

False

(T/F) The range of a set of data values is the largest value in the data set.

False

(T/F) The standard deviation is the square of the variance.

False

(T/F) The standard deviation of a data set can be positive or negative.

False

(T/F) The sum of the absolute deviations from the mean of a data set is always equal to 0.

False

The range is not influenced by an outlying value in a data set.

False

(T/F) The coefficient of variation can be used to compare the variability of data sets that have different units.

True

(T/F) The mean absolute deviation is a measure of variability.

True

(T/F) The middle 50 percent of an ordered set of data values constitutes the interquartile range.

True

(T/F) The sum of the absolute deviations from the mean for any data set may equal zero.

True

(T/F) The unit for the variance of a data set is the square of the unit for the variable associated with the data set.

True

A sample of 10 student s was asked by their instructor to record the number of hours they spent studying for a given exam from the time the exam was announced in class. The following data values were recorded for the number of hours: 12 15 8 9 14 8 17 14 8 15 The median number of hours spent studying for this sample is a) 10 b) 11 c) 12 d) 13

d) 13

Examine the following data set: 4 5 7 7 8 6 5 8 7 What is the mode value for this data set? a) 4 b) 5 c) 6 d) 7

d) 7

Examine the following data set: 4 5 7 7 8 6 5 8 7 9 8 6 4 What is the mode or modes for this data set? a) 4 b) 7 c) 8 d) 7 and 8

d) 7 and 8

What type of distribution is described by the following information? Mean = 5.5 Median = 5.3 Mode = 4.4 a) negatively skewed b) symmetrical c) bimodal d) positively skewed

d) positively skewed

(T/F) The value of the mean absolute deviation represents the number of standard deviations above or below the mean of the data set.

False

Which of the following is true for a negatively skewed distribution? a) mode = median = mean b) mean < median < mode c) mode < median < mean d) median < mode < mean

b) mean < median < mode

Examine the following data set: 4 3 7 7 8 7 4 8 6 What is the mean for this data set? a) 4 b) 5 c) 6 d) 7

c) 6

Examine the following data set: 3 2 7 7 8 7 3 8 5 What is the median value for this data set? a) 5 b) 6 c) 7 d) 8

c) 7

A statement is made that more students are purchasing graphing calculators than any other type of calculator. Which measure is being used here? a) Mean b) Median c) Mode d) Noneof the above

c) mode

which of the following is true for a positively skewed distribution? a) mode = median = mean b) mean < median < mode c) mode < median < mean d) median < mode < mean

c) mode < median < mean

A cyclist recorded the number of miles per day that she cycled for five days. The recordings were as follows: 13, 10, 12, 10, 11. The mean (average number of miles she cycled per day was a) 13 b) 11 c) 10 d) 11.2

d) 11.2