6th grade statistics and probability

Example

Find the mean of: 11, 14, 15, 19, 10, 9

1. 11 + 14 + 15 + 19 + 10 + 9 = 78
2. 78 ÷ 6 = 13

Answer: 13

Example

Hiro has taken 3 tests. The scores of the first 2 are 96, 86. The mean of all 3 is 90. What did Hiro score on the last test?

1. 90 × 3 = 270
2. 96 + 86 = 182
3. 270 − 182 = 88

Answer: 88

Example

Find the lower quartile (Q1) of: 2, 9, 16, 20, 22, 23, 27, 33, 35, 37, 40

1. Median = 23
2. Q1 = 16, Q3 = 35

Answer: 16

Example

Is this a statistical question? “How many legs does a spider have?”

1. There is one fixed answer, so it is not statistical.

Answer: No

Example

Data (kg of recycling collected each week): 11, 25, 60, 26, 34. Find the mean.

1. 11 + 25 + 60 + 26 + 34 = 156
2. 156 ÷ 5 = 31.2

Answer: 31.2

Example

Find the median: 18, 40, 34, 28, 3, 21

1. 3, 18, 21, 28, 34, 40
2. (21 + 28) ÷ 2 = 24.5

Answer: 24.5

Example

What is the mode of: 2, 13, 18, 1, 18, 18, 20, 3?

1. 18 appears 3 times.

Answer: 18

Example

Find the lower quartile (Q1) of: 20, 48, 33, 36, 8, 14, 32, 2, 45, 2, 39

1. 2, 2, 8, 14, 20, 32, 33, 36, 39, 45, 48
2. Median = 32
3. Q1 = 8

Answer: 8

Example

The mean of 18, 24, 15, 21, 22 is 20. Find the mean absolute deviation.

1. Distances: 2, 4, 5, 1, 2
2. 2 + 4 + 5 + 1 + 2 = 14
3. 14 ÷ 5 = 2.8

Answer: 2.8

Example

Data: 16, 14, 13, 10, 18, 88. If the outlier 88 is removed, what happens to the mean?

1. With: 26.5; without: 14.2
2. It decreases.

Answer: It decreases