CW 3/22 Basics of normal distribution

Given the following histogram, how can we describe the shape of the data?

• Skewed

• Symmetric

• Uniform

• Bimodal

Which of the following statements are true?

I. The distribution is skewed.

II. The distribution is uniform

III. The distribution is symmetric.

IV. This is not a histogram, it is a bar chart and hence the first three statements can't possibly apply.

• I only

• III only

• I and II only

• I,III and IV only

• All

Which of the following statements about the normal curve are true?

• A. I and II only

• B. II and IV only

• C. I and III only

• D. I, II, III, and IV

Which proportion of the curve is the shaded area?

• A. greater than 0.50

• B. less than 125

• C. greater than 0.90

• D. less than 0.50

• E. equal to 0.50

Tags

CCSS.HSS.ID.A.4

Using the Standard Normal (z) Distribution Table, what is the area to the right of z=1.64 under the standard normal curve? Explain how you find it.

• .9495 because I found the intersection of 1.6 and .04 from the z-table

• .0505 because I found the area tot he left and thenI subtracted it from the total area=1

• -.0678 becaus eI found the area to the left and subtracted 1 from the value I found on the table

• -0.98 because I found the closest area to .1640 and then found the z-score for it.

Tags

CCSS.HSS.ID.A.4

The variable [z] is normally distributed. What is the probability P(z < -0.63) ? (What is the probability of finding a z-score less than -0.63?)

• . 0.1321

• 0.2643

• 0.2676

• 0.3132

• 0.5132

Tags

CCSS.HSS.ID.A.4

The variable z is normally distributed. What is the value of a , if P(z < a) = 0.39 (if the probability of find a z-core less than a is found by using the area of 0.39 ?) (Hint: use probability to find the zscore)

• −1.23

• −0.28

• 0.35

• 0.65

• 1.23

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CCSS.HSS.ID.A.4

Using the Standard Normal (z) Distribution Table, what is the area to the right of 0.72 under the standard normal curve?

• A. 0.1179

• B. 0.2358

• C. 0.2642

• D. 0.3821

• E. 0.7642

Tags

CCSS.HSS.ID.A.4

Using the Standard Normal (z) Distribution Table, what is the area under the standard normal curve to the left of z=1.25?

• A. 0.1056

• B. 0.3944

• C. 0.4472

• D. 0.6056

• E. 0.8944

Tags

CCSS.HSS.ID.A.4

On a standardized test, a score of 80 falls exactly 2 standard deviations below the mean. If the standard deviation for the test is 4, what is the mean score for the test?

• A.84

• B. 86

• C. 88

• D. 90

• E. 94