Question 5) The following is a physical activity score for two groups in study. The higher score means the more physical activity

(Part a and b 3 points and part c and d 1.5 point)

Group

n

s

Control

100

40

8

Intervention

100

50

10

a) What statistical test researcher should use?

1.Two sample T-test when population variance is known

2.One sample T-test when population variance is unknown

3.One sample T-test when population variance is known

4.Two samples T-test when population Variance is unknown

b) What is the Pooled variance for these two groups? (Use S pooled by using S²p= (n1-1) * S²1 + (n2-1) * S²2/ n1 +n2 -2)

1.82

2.2.80

3.1.50

4.2.00

d)c) What is the value of T statistics? (use xbar1-xbar2 - 0 divided by square root of (s²p/n1 + s²p/n1))

1.-5.60

2.-3.00

3.5.60

4.-7.81

d) Can we conclude the mean of physical activity is different for intervention as compare to control at alpha .01?

1. Yes, because our absolute test statistics is greater than T value from T table

2. No, because our absolute test statistics is less than T value from T table