Questions: Find the deviations from the mean for the set of ACT test score data: 22, 25, 18, 20, 20. (Simplify your answers.) Score Deviation from mean 22 25 18 20 20

Find the deviations from the mean for the set of ACT test score data: 22, 25, 18, 20, 20. 

(Simplify your answers.)
Score Deviation from mean
22

25

18

20

20
Transcript text: Find the deviations from the mean for the set of ACT test score data: $22,25,18,20,20$. (Simplify your answers.) Score Deviation from mean 22 $\square$ 25 $\square$ 18 $\square$ 20 $\square$ 20 $\square$
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Solution

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Solution Steps

Step 1: Calculate the Mean

To find the mean (\( \mu \)) of the ACT test scores \( 22, 25, 18, 20, 20 \), we use the formula:

\[ \mu = \frac{\sum_{i=1}^N x_i}{N} = \frac{22 + 25 + 18 + 20 + 20}{5} = \frac{105}{5} = 21.0 \]

Thus, the mean of the data is \( \mu = 21.0 \).

Step 2: Calculate Deviations from the Mean

Next, we calculate the deviations from the mean for each score. The deviation for each score \( x_i \) is given by:

\[ \text{Deviation} = x_i - \mu \]

Calculating the deviations:

  • For \( 22 \): \( 22 - 21.0 = 1.0 \)
  • For \( 25 \): \( 25 - 21.0 = 4.0 \)
  • For \( 18 \): \( 18 - 21.0 = -3.0 \)
  • For \( 20 \): \( 20 - 21.0 = -1.0 \)
  • For \( 20 \): \( 20 - 21.0 = -1.0 \)

The deviations from the mean are as follows:

  • Score: \( 22 \), Deviation: \( 1.0 \)
  • Score: \( 25 \), Deviation: \( 4.0 \)
  • Score: \( 18 \), Deviation: \( -3.0 \)
  • Score: \( 20 \), Deviation: \( -1.0 \)
  • Score: \( 20 \), Deviation: \( -1.0 \)

Final Answer

The mean of the ACT test scores is \( \mu = 21.0 \) and the deviations from the mean are:

  • For score \( 22 \): \( 1.0 \)
  • For score \( 25 \): \( 4.0 \)
  • For score \( 18 \): \( -3.0 \)
  • For score \( 20 \): \( -1.0 \)
  • For score \( 20 \): \( -1.0 \)

Thus, the final answer is:

\[ \boxed{\text{Mean} = 21.0, \text{Deviations} = \{1.0, 4.0, -3.0, -1.0, -1.0\}} \]

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