Question 1

Which of the following best describes what a z-score represents in a standard normal distribution?

Accepted Answer

The number of standard deviations a value is from the mean.

Question 2

Given $$P(Z \u003c 1.21)$$, which of the following steps correctly finds the probability using the z-table?

Accepted Answer

Look up 1.21 in the z-table and use the value as the probability.

Question 3

If you want to find $$P(Z \u003e -0.44)$$, which formula should you use?

Accepted Answer

$$P(Z \u003e -0.44) = 1 - P(Z \u003c -0.44)$$

Question 4

A medical test result has a z-score of 2.27. What is the probability that a randomly selected result from the population is greater than this value?

Accepted Answer

$$P(Z \u003e 2.27) = 1 - P(Z \u003c 2.27)$$

Question 5

Which of the following correctly finds the probability between two z-scores, $$a$$ and $$b$$ ($$a \u003c b$$)?

Accepted Answer

$$P(a \u003c Z \u003c b) = P(Z \u003c b) - P(Z \u003c a)$$

Question 6

Suppose the area under the standard normal curve to the left of $$z is$$ $$0.6331. $$What is the $$z-$$score?

Accepted Answer

Find $$z$$ such that $$P(Z \u003c z) = 0.6331$$ using the z-table.

Question 7

A researcher finds that $$P(Z \u003c z) = 0.9357. $$What is the corresponding $$z-$$score?

Accepted Answer

Look up $$0.9357 in $$the z-table and find the corresponding $$z$$ value.

Question 8

Which of the following statements about the standard normal distribution is TRUE?

Accepted Answer

The mean is $$0$$ and the standard deviation is $$1.$$

Question 9

A student wants to find $$P(Z \u003c -0.81)$$ using a calculator. Which calculator function should they use?

Accepted Answer

normalcdf

Question 10

If $$P(Z \u003c z) = 0.8051$$, what is the $$z-$$score?

Accepted Answer

Find $$z$$ such that the cumulative area to the left is $$0.8051$$ using the z-table.

Question 11

Which of the following is the correct way to find the probability to the right of a $$z-$$score using the z-table?

Accepted Answer

$$P(Z \u003e z) = 1 - P(Z \u003c z)$$

Question 12

A pharmaceutical company wants to know the probability that a randomly selected patient’s test result falls between $$z = -0.64$$ and $$z = 2.27. $$Which formula should they use?

Accepted Answer

$$P(-0.64 \u003c Z \u003c 2.27) = P(Z \u003c 2.27) - P(Z \u003c -0.64)$$

Question 13

If the area under the standard normal curve to the left of $$z is$$ $$0.2611$$, what is the $$z-$$score?

Accepted Answer

Look up $$0.2611 in $$the z-table and find the corresponding $$z$$ value.

Question 14

A psychologist wants to know the probability that a test score is less than $$z = 0.8. $$Which of the following is the correct approach?

Accepted Answer

Look up $$0.8 in $$the z-table and use the value as the probability.

Question 15

Which calculator function is used to find the $$z-$$score given a probability (area to the left)?

Accepted Answer

invNorm

Question 16

If $$P(Z \u003c z) = 0.9884$$, what is the $$z-$$score?

Accepted Answer

Look up $$0.9884 in $$the z-table and find the corresponding $$z$$ value.

Question 17

A biologist wants to find the probability that a measurement is greater than $$z = 1.14. $$Which of the following is correct?

Accepted Answer

$$P(Z \u003e 1.14) = 1 - P(Z \u003c 1.14)$$

Question 18

Which of the following is TRUE about the values in the z-table provided?

Accepted Answer

They represent cumulative probabilities from the left of the standard normal curve.

Using the Standard Normal Distribution and z-Tables in Statistics

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