Chen loves to write poems. He has decided to dedicate time each day to writing his poems. He records the number of minutes he spends writing each day for 10 days. The dataset for the 10 days is (9,25,14,16,22,19,22,13,14,14)

. What is the measure of variability of this dataset?(1 point)
Responses

15
15

16.8
16.8

14
14

16
you have to pick one of these answers

1 answer

To find the measure of variability of the dataset, we can calculate the standard deviation.

First, let's find the mean (average) of the dataset:

  1. Calculate the sum of the data points: \( 9 + 25 + 14 + 16 + 22 + 19 + 22 + 13 + 14 + 14 = 9 + 25 = 34 \) \( 34 + 14 = 48 \) \( 48 + 16 = 64 \) \( 64 + 22 = 86 \) \( 86 + 19 = 105 \) \( 105 + 22 = 127 \) \( 127 + 13 = 140 \) \( 140 + 14 = 154 \) \( 154 + 14 = 168 \)

    The sum is \( 168 \).

  2. Calculate the mean: \[ \text{Mean} = \frac{\text{Sum of data points}}{\text{Number of data points}} = \frac{168}{10} = 16.8 \]

Next, we calculate each data point's deviation from the mean and then square those deviations:

  • \( (9 - 16.8)^2 = (-7.8)^2 = 60.84 \)
  • \( (25 - 16.8)^2 = (8.2)^2 = 67.24 \)
  • \( (14 - 16.8)^2 = (-2.8)^2 = 7.84 \)
  • \( (16 - 16.8)^2 = (-0.8)^2 = 0.64 \)
  • \( (22 - 16.8)^2 = (5.2)^2 = 27.04 \)
  • \( (19 - 16.8)^2 = (2.2)^2 = 4.84 \)
  • \( (22 - 16.8)^2 = (5.2)^2 = 27.04 \)
  • \( (13 - 16.8)^2 = (-3.8)^2 = 14.44 \)
  • \( (14 - 16.8)^2 = (-2.8)^2 = 7.84 \)
  • \( (14 - 16.8)^2 = (-2.8)^2 = 7.84 \)

Now, let's sum these squared deviations: \[ 60.84 + 67.24 + 7.84 + 0.64 + 27.04 + 4.84 + 27.04 + 14.44 + 7.84 + 7.84 = 300.6 \]

Now, we find the variance: \[ \text{Variance} = \frac{\text{Sum of squared deviations}}{\text{Number of data points}} = \frac{300.6}{10} = 30.06 \]

Finally, we take the square root to find the standard deviation: \[ \text{Standard Deviation} = \sqrt{30.06} \approx 5.48 \]

However, we don't see a match with the given responses. It seems like we are supposed to find a measure of variability that aligns with one of the options listed (likely the range).

The range is: \[ \text{Range} = \text{Max} - \text{Min} = 25 - 9 = 16 \]

So the best answer based on the options provided is 16.