Understanding Z-Scores and Normal Distribution

This video tutorial explains how to use the normal distribution calculator from onlinestatbook.com to determine the probability of a z-score falling within specified intervals. It covers the concept of z-scores, the standard normal distribution, and provides step-by-step instructions for calculating probabilities for z-scores greater than 0.8, less than -1.5, between -2.3 and 1.2, and outside -1.7 and 1.9. The tutorial emphasizes using the calculator to find these probabilities and converting them into percentages.

What tool is introduced in the video for calculating probabilities in a normal distribution?

• SPSS

• Excel

• onlinestatbook.com

• R Studio

What is a z-score?

• The number of standard deviations a data value is from the mean

• A measure of central tendency

• A measure of variability

• The mean of a data set

What is the mean of the standard normal distribution?

• 1

• 0

• 100

• 50

What is the probability that a z-score is greater than 0.8?

• 0.212

• 0.788

• 0.100

• 0.500

Which option should be selected in the calculator to find the probability of a z-score being less than a given value?

• Above

• Below

• Outside

• Between

What is the probability that a z-score is less than -1.5?

• 0.933

• 0.067

• 0.150

• 0.500

What is the probability that a z-score is between -2.3 and 1.2?

• 0.500

• 0.874

• 0.250

• 0.126

Which option should be selected in the calculator to find the probability of a z-score being outside two given values?

• Below

• Above

• Outside

• Between

What is the probability that a z-score is less than -1.7 or greater than 1.9?

• 0.500

• 0.073

• 0.200

• 0.927

What is the standard deviation of the standard normal distribution?

• 1

• 5

• 0

• 10