STATISTICS FOR PSYCHOLOGY

Statistics for Psychology



Statistics for Psychology

Chapter 2

11.

(a) Mean = (2+2+0+5+1+4+1+3+0+0+1+4+4+0+1+4+3+4+2+1+0)/21=42/21=2

(b) For Median

0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 2, 2, 3, 3, 4, 4, 4, 4, 4, 5

Median = 2

(c) Squared deviations:

x

x-mean

(x-mean)^2

2

0

0

2

0

0

0

-2

4

5

3

9

1

-1

1

4

2

4

1

-1

1

3

1

1

0

-2

4

0

-2

4

1

-1

1

4

2

4

4

2

4

0

-2

4

1

-1

1

4

2

4

3

1

1

4

2

4

2

0

0

1

-1

1

0

-2

4

sum

56

Sum of squared deviation = 56

(d) Variance = Sum of squared deviation/n - 1 = 56/(21 - 1) = 56/20 = 2.8

(e) Standard deviation = vvariance = v2.8 = 1.673

12.

(a) Mean = sum/21 = 6562/5 = 1312.4

(b) For Median

1112, 1,245, 1361, 1372, 1,472

Median = middle number = 1361

(c) squared deviations

x

x-mean

(x-mean)^2

1112

-200.4

40160.16

1245

-67.4

4542.76

1361

48.6

2361.96

1372

59.6

3552.16

1472

159.6

25472.16

Sum

76089.2

Sum of squared deviations = 76089.2

(d)Variance = = 76089.2/(5 - ...