Normal Distribution Pre-Test

Joanne's Z-score is -1.5.  What does this mean?

• She didn't take the test yet.

• She scored 1.5 standard deviations below the mean.

• She scored 1.5 standard deviations above the mean.

• She did better than most people.

If Gonzalo's score is 87, the class mean is 82, and the s = 4, what is Gonzalo's z-score?

• -1.25

• +1.25

• +1.20

• +1.02

If the value we are looking for is smaller than the mean, the value of z is:

• Not enough information

• Negative

• Positive

• 0

If the value we are looking for is the same as the mean, the value of z is:

• Not enough information

• Positive

• Negative

• 0

What's the probability x > 17?

(Mean = 15, Standard dev = 3)

• 0.7486

• 0.7454

• 0.2514

• 0.2546

What's the probability of x < 13 ?

(Mean = 20, Standard dev = 6.5)

• 0.1423

• 0.1401

• 0.0446

• 0.0359

35 is...?

• standard deviation

• mean

• variance

The shape of a normal distribution curve is typically:

• Asymmetrical with multiple peaks

• Symmetrical and bell-shaped

• Irregular and random

• Linear with a constant slope

5. A “z-score” is useful in probability because it

• A) Finds exact values without any calculations

• B) Helps standardize data for comparison

• C) Indicates the most frequent value in data

• D) Measures only the largest values

Which one of these is NOT a property of Normal Distribution?

• Bell-shaped curve

• Mean, median and mode are equal

• Curve is continuous

• Curve is asymmetric