ch 3 bus stats

which of the following symbols represents the mean of a sample

x̅

The closing stock price of MNM Corporation for the last 7 trading days is shown below. Day Stock Price 1 24 2 27 3 24 4 28 5 25 6 30 7 31 The mean is

27

the sum of deviations of the individual data elements from their mean is

always equal to zero

If the data distribution is symmetric, the skewness is

0

which of the following symbols represents the mean of the population?

,u

the correlation coefficient ranges between

-1 and +1

which of the following symbols represents the variance of the population

0^2

The weights (in pounds) of a sample of 36 individuals were recorded and the following statistics were calculated. mean = 160 range = 60 mode = 165 variance = 324 median = 170 The coefficient of variation equals

11.25% s= square root of 324 =18 18/160 x 100%= 11.25

a researcher has collected the following sample data 15 12 16 18 15 16 17 15 12 14 the 75th percentile is

16 L75= 75/100 (10+1)= 8.25 = 16 + .25 (17-16)=16.25

a group of students had dinner at a local restaurant. the total bill for the dinner was $364.99. each student paid his/her equal share of the bill which was $21.47. how many students were at the dinner?

17 364.99/21.47

a researcher has collected the following sample data 13 15 12 13 12 the interquartile range is

2 L25= 25/100 (5+1)= 1.5 = 12 + .5 (12-12)= 12 L75= 75/100 (5+1)= 4.5 = 13 +.5 (15-13)= 14 IQR= 14-12=2

the geometric mean of 1,1, and 8 is

2.0 (1)(1)(8)= 8 cube root of 8= 2

the geometric mean of 1,3,4,6 is

2.63 (1)(3)(4)(6)=48 fourth root of 48= 2.63

The closing stock price of MNM Corporation for the last 7 trading days is shown below. Day Stock Price 1 24 2 27 3 24 4 28 5 25 6 30 7 31 The mode is

24

the standard deviation of a sample of 81 observations equals 49. the variance of the sample equals

2401 49^2=2401

the first quartile is the same as the

25th percentile

The closing stock price of MNM Corporation for the last 7 trading days is shown below. Day Stock Price 1 24 2 27 3 24 4 28 5 25 6 30 7 31 the median is

27

The hourly wages of a sample of 130 system analysts are given below. mean = 60 range = 20 mode = 73 variance = 324 median = 74 The coefficient of variation equals

30% s= square root of s^2 s= square root of 324 s=18 18/60x 100%= 30%

the geometric mean of 3,4,6 is

4.16 (3)(4)(6)= 72 cube root of 72= 4.16

the geometric mean of 3,5 and 6 is

4.48 (3)(5)(6)=90 cube root of 90= 4.48

the median of the sample will always equal the

50th percentile

growth factors for a population of Atlanta in the past 5 years have been 1,2,3,4, and 5. the geometric mean is

5th root of 120 (1)(2)(3)(4)(5)=120

The closing stock price of MNM Corporation for the last 7 trading days is shown below. Day Stock Price 1 24 2 27 3 24 4 28 5 25 6 30 7 31 The variance is

6.428

the empirical rule states that, for data having a bell-shaped distribution, the percentage of data values being within one standard deviation of the mean is approximately

68%

the variance of a sample of 100 observations equals 64. the standard deviation of the sample equals

8 s^2= 64 s=square root of 64 s=8

the mean of the sample

can assume any value between the highest and the lowest value in the sample.

when computing the mean, the smallest value

can be any value

from a population of size 1000, a random sample of 100 is selected. the mean of the sample

can be larger, smaller, or equal to the mean of the population

from a population size of 500, a random sample of 50 items is selected. the mode of the sample

can be larger, smaller, or equal to the mode of the population

the coefficient of correlation

cannot be larger than 1

the median is a measure of

central location

statements about the proportion of the data values that must be within a specified number of standard deviations of the mean can be made using

chebyshev's theorem

the mean of a sample is

computed by summing all the data values and dividing the sum by the number of items

the sample variance

could be smaller, equal to, or larger than the true value of the population variance

which of the following is not a measure of variability of a single variable

covariance

In computing descriptive statistics from grouped data,

data values are treated as if they occur at the midpoint of a class

the geometric mean of 4 observations is the

fourth root of the product of the 4 observations

When data is positively skewed, the mean will usually be

greater than the median

which of the following is a measure of variability?

interquartile range

geometric mean is a measure of

location

geometric mean is the measure of

location

generally, which one of the following is the least appropriate measure of central tendency for a data set that contains outliers

mean

the coefficient of variation indicates how large the standard deviation is relative to the

mean

the measure of location which is most likely to be influenced by extreme values in the data set is the

mean

which of the following provides a measure of central tendency for the data

mean

the 50th percentile is the

median

the value which has half the observations above it and half the observations above it is called the

median

the most frequently occurring value of a data set is called the

mode

In computing the mean of a sample, the value of ∑xi is divided by

n

which of the following symbols represents the size of the sample

n

for data skewed to the left, the skewness is

negative

If two groups of numbers have the same mean, then

other measures of location need not be the same.

if two groups of numbers have the same mean, then

other measures of location need not be the same.

the pth percentile is a value such that approximately

p percent of the observations are less than the value and (100-p) percent are more than this value

in a box plot, data value x is considered an outlier if

x< Q1- 1.5 (IQR) or x>Q3+ 1.5(IQR)

μ is an example of a

population parameter

When the data are skewed to the right, the measure of Skewness will be

positive

Positive values of covariance indicate

positive relation between the independent and the dependent variables

the difference between the largest and smallest value of a data values is the

range

the measure of variability easiest to compute, but seldom used as the only measure, is the

range

the measure of variability that is influenced most by extreme values is the

range

an important numerical measure of the shape of distribution is the

skewness

the descriptive measure of variability that is based on the concept of variation about the mean is the

standard deviation

the coefficient of variance is the

standard deviation divided by the mean times 100

a numerical value used as a summary of a sample is known as a sample

statistic

the interquartile range is

the difference between the third and first quartile

the percentage of data values that must be within one, two, and three standard deviations of the mean for data having a bell-shaped distribution can be determined using

the empirical rule

in a five number summary, which of the following is not used for data summarization

the mean

the symbol 0 is used to represent the

the standard deviation of the population

the 75th percentile is referred to as the _______ quartile

third

the measure of dispersion which is not measured in the same units as the original data is

variance

which of the following descriptive statistics is not measured in the same units as the data

variance

the symbol 0^2 is used to represent the

variance of the population

A mean computed in such a way that each data value is given a weight reflecting its importance is referred to as

weighted mean

the ________ can be interpreted as the number of standard deviations a data value is from the mean of all the data values

z-score

which of the following symbols represents the mean of the population

μ

which of the following symbols represents the standard deviation of the population

σ