HW #2

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%

A researcher has collected the following sample data. The mean of the sample is 5. The standard deviation is? 3 5 12 3 2

4.062

The variance of a sample was reported to be 144. The report indicated that Σ(x-average)^2= 7200. What has been the sample size?

51

The closing stock price of MNM Corporation for the last 7 trading days is shown below. The variance is? Day Stock Price 1 84 2 87 3 84 4 88 5 85 6 90 7 91

First find the mean: (84+87+84+88+85+90+91)/7 = 87 The sample variance is equal to: , where Xi is the observed value and xbar is the mean of the observations The variance is = 8

A researcher has collected the following sample data. The mean of the sample is 5. The interquartile range is? 3 5 12 3 2

IQR = 2

A researcher has collected the following sample data. The 75th percentile is? 5 12 6 8 5 6 7 5 12 4

In order to find a percentile, first you have to arrange the data from smallest to largest: Now multiply percentile with no.s in data = 10*75% = 7.5 It is not a whole number hence round it up to nearest whole number i.e 8. After finding the percentile no. count in your data set from smallest to largest till the no. calculated (the location of 8th number on data set.) Here in the data set the no. which is on 8th location is 8. Hence the 75th percentile of the data set is (a). i.e 8

A group of students had dinner at a local restaurant. The total bill for the dinner was $414.70. Each student paid his/her equal share of the bill, which was $18.85. How many student's were at the dinner?

Number of students = Total bill / bill paid per student = 414.7 / 18.85 = 22

From a population of size 1,000, a random sample of 100 items is selected. The mean of the sample

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

From a population of size 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

Given the following information: Standard deviation = 8 Coefficient of variation = 64% The mean would then be

coef v = stdv / mean *100 64=8/ mean * 100 mean= 8*100 /64 =12.5

Which of the following symbols represents the size of the sample

n (lower case)

μ is an example of a

population parameter

The closing stock price of MNM Corporation for the last 7 trading days is shown below. The range is? Day Stock Price 1 84 2 87 3 84 4 88 5 85 6 90 7 91

range= maximum - minimum 91-84= 7

A researcher has collected the following sample data. The median is? 5 12 6 8 5 6 7 5 12 4

6

The value of the sum of the deviations from the mean, i.e.,Σ(x-average) must always be ?

0

The standard deviation of a sample was reported to be 20. The report indicated that Σ(x-average)^2 = 7200. What has been the sample size?

19

The heights (in inches) of 25 individuals were recorded and the following statistics were calculated. The coefficient of variation equals? mean = 70 range = 20 mode = 73 variance = 784 median = 74

40%

The closing stock price of MNM Corporation for the last 7 trading days is shown below. The median is? Day Stock Price 1 84 2 87 3 84 4 88 5 85 6 90 7 91

87

The variance of a sample of 169 observations equals 576. The standard deviation of the sample equals

Variance = (stdev)2 Std dev = sqrt(variance) = sqrt(576) = 24

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

coefficient of variation =(std deviation/mean)*100 = (variance^1/2) / mean * 100 11.25%