what is z score

If two samples have means of 24 and 28 and standard deviations of 4 and 6, with 12 and 15 as the sizes, find the z score for difference of two population means. => 2.07 or 7.73 or 1.07 or 1.93..

Find the z scores of three students who had a score of 93, 80, 84 in an examination for a pre-medicine course which has a mean of 84 and a standard deviation of 4. => 9, - 4, 0 or 23.25, 20, 21 or 2.25, - 1, 0 or - 2.25, 1, 0..

Which of the following statement(s) is/are true? I. If a student secured 75th percentile in an exam, then it means that he scored 75 out of 100. II. A statistic that tells the number of standard deviations a data value is above or below the mean is called z score. III...

Recognize the incorrect statement(s). I. When all data for a variable are transformed into z scores, the resulting distribution will have a mean of 1 and a standard deviation of 0. II. The z score represents the number of standard deviations that a data value..

The reaction time to a stimulus for a certain drug has a mean of 2.5 seconds and a standard deviation of 0.3 seconds. Find the z score for a reaction time of 3.1 seconds. => 2 or 18.67 or 0.2 or 7.33..

The average number of pens sold by a shopkeeper in the first half and second half of a month are 315 and 300. If the standard deviations are 30 and 35, then find the z score value and verify the difference between both the means at 90% of confidence. => 0.106, both the means do ..

Two populations have means of 29.5 and 28 and variances of 6 and 7.8. If the sizes are 30 and 43, then find the z score values. Verify whether the mean of the first population is greater than that of the other at 99% of confidence or not. => 3.93, not greater or 0.57, greater or..

If the average number of steps between any two stairs of a 20 storyed building is 14 and that of 25 storyed building is 12 with the variances 8 and 10.23, find the z score value and verify if the mean number of steps between any two stairs of both the buildings differ significan..

A person verified the records of past 20 years of one estate and that of past 18 years of another estate. The average number of families leaving in the first estate was found as 23 and that of second estate as 20. If the standard deviations were 6 and 8, find the z score value a..

What is the formula to find the z score for the difference between two population means, if X 1 and X 2 are the sample means, s 1 2 and s 2 2 are the sample variances and n 1 and n 2 are the size of the samples? (Assume both n 1 and n 2 are greater than..