RESEARCH METHODOLOGY

STATISTICAL TECHNIQUES AND TOOLS

SAMPLING DISTRIBUTION

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
The mean and standard deviation of a population are 200 and 20, respectively. To find the probability of randomly selecting a value that is 190, which z-score formula would you use?
A
z=(200-190)/(20/√25)
B
z=(190-200)/(20/√25)
C
z=(200-190)/20
D
z=(190-200)/20
Explanation: 

Detailed explanation-1: -The z-score of a value is the count of the number of standard deviations between the value and the mean of the set. You can find it by subtracting the value from the mean, and dividing the result by the standard deviation.

Detailed explanation-2: -The formula for calculating a z-score is z = (x-)/, where x is the raw score, is the population mean, and is the population standard deviation.

Detailed explanation-3: -What is the z-score of a value of 27, given a set mean of 24, and a standard deviation of 2? To find the z-score we need to divide the difference between the value, 27, and the mean, 24, by the standard deviation of the set, 2. This indicates that 27 is 1.5 standard deviations above the mean.

There is 1 question to complete.