Math Problem Statement

A variable xx is normally distributed with mean 24 and standard deviation 5. Round your answers to the nearest hundredth as needed.

a) Determine the zz-score for x=27x=27.

z=z=

b) Determine the zz-score for x=22x=22.

z=z=

c) What value of xx has a zz-score of 1.21.2?

x=x=

d) What value of xx has a zz-score of 00?

x=x=

e) What value of xx has a zz-score of 00?

x=x=

Solution

To solve these problems, we need to use the z-score formula, which is:

z=xμσz = \frac{{x - \mu}}{{\sigma}}

Where:

  • zz is the z-score,
  • xx is the value of the variable,
  • μ\mu is the mean, and
  • σ\sigma is the standard deviation.

In this case, the mean μ=24\mu = 24 and the standard deviation σ=5\sigma = 5.


a) Determine the zz-score for x=27x = 27

Using the formula:

z=27245=35=0.60z = \frac{{27 - 24}}{{5}} = \frac{3}{5} = 0.60

So, z=0.60z = 0.60.


b) Determine the zz-score for x=22x = 22

z=22245=25=0.40z = \frac{{22 - 24}}{{5}} = \frac{-2}{5} = -0.40

So, z=0.40z = -0.40.


c) What value of xx has a zz-score of 1.2?

Here, we solve for xx using the z-score formula:

1.2=x2451.2 = \frac{{x - 24}}{{5}}

Multiplying both sides by 5:

x24=6x - 24 = 6

So, x=30x = 30.


d) What value of xx has a zz-score of 0?

If the z-score is 0, the value of xx is equal to the mean, since:

z=x245=0z = \frac{{x - 24}}{{5}} = 0

So, x=24x = 24.


e) What value of xx has a zz-score of 0? (This part repeats d)

Again, x=24x = 24, as explained in part d.


Let me know if you need further details or clarifications!


5 Related Questions:

  1. How is the z-score used to find probabilities in a normal distribution?
  2. Can you calculate the probability that xx falls between two values given their z-scores?
  3. What does a negative z-score signify in terms of data position?
  4. How do you interpret a z-score of exactly 1 or -1?
  5. How would the z-scores change if the standard deviation was smaller or larger?

Tip:

A z-score of 0 means the data point is exactly at the mean of the distribution!

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Math Problem Analysis

Mathematical Concepts

Statistics
Normal Distribution
Z-scores

Formulas

z = (x - μ) / σ

Theorems

Properties of Normal Distribution

Suitable Grade Level

Grades 10-12