Descriptive stats- Measures of dispersion

Question 1

Range

Answer 1

✔: It’s easy to calculate
✘: Distorted by extreme values

Question 2

Variance

Answer 2

The spread of scores around the mean. Small variance- scores are similar, consistent and close to the mean
Large variance- Scores are at a larger distance from the mean, suggests an issue

Question 3

Standard deviation

Answer 3

The square root of the variance. Tells us the average amount a no. differs from the mean

Question 4

Variance- calculation

Answer 4

1. Calculate mean for your scores
2. Find variance by subtracting mean from each no. in your sample
3. Square results of thses calculations
4. Add squared no. together to find sum of squares
5. Divide sum of squares by (n-1) n- tot. no. in sample
   Sum of D2/(n-1)

Question 5

Standard deviation-calculation

Answer 5

square root answer from variance