Business Statistics Test 2

In a class of 22 students, Sam and John got 10th position. What is the percentile / class rank?

56.82%

Using 35, 46, 49, 63, 65, 72, 72, 82, 82, 96 What is the percentile rank of a score of 82?

80%

Disadvantage of Chebyshev's Inequality

For most data sets it only provides a rough approximation

Chebyshev's Inequality

theory describing the maximum number of extreme values in a probability distribution

Normally distributed WISC-IV scores have a mean of 100 and a standard deviation of 15. -What is the probability of selecting someone with a WISC-IV score between 52 and 86.

z = (x-µ)/σ z = (86 - 100) / 15 z = -0.933 AL = .17619 Now for the 52 z = (x-µ)/σ z = (52 - 100) / 15 z = -3.2 AL = .00069 So, to solve .17619- .00069 = .1755 ANSWER

The mean score on an information survey is 40, with a standard deviation of 5. Between which two scores must this mean lie to represent 8/9 of the data set?

1 - 1 /k^2 = 8/9 1 - 8/9 = 1/k^2 1/9 = 1/k^2 k^2 = 9 k = 3 Lower limit: 40 - (5)(3) = 40 - 15 = 25 Upper limit: 40 + 15 = 55 Solution: The mean score of 40 with a standard deviation of 5 must lie between 25 and 55 to represent 88.89% of the data set.

A company makes 225,000 Electric Dog Polishers a year. On average 2.13% of the Electric Dog Polishers are defective. A random sample of 247 Electric Dog Polishers are were selected for quality control. -Calculate the mean and standard deviation of the defective Electric Dog Polishers in the sample.

Mean = 5.26 Standard Deviation = 2.26

What is an unusually small or unusually large data value called? What effect to a large data set may be caused by this?

Outlier, only affects the mean