Problem 15

Not random, but we have to assume representative

Independent: Not independent, since wind speeds are generally related.

The distibution is nearly normal, NPP is suitably straight.

(-41.32, -32.54)

We are 90% confident that the true interval of wind speeds lies within this range.

Problem 17

t=1.75

We are 90% confident that the true mean difference is between the interval 1.6 and 13.05

Problem 19

We’d use paired data, so a paired t test.

h0: difference=0 ha: diff =/= 0

Workers are randomly selected. Assume workers are less than 10% of population: independent Distuibtion is suitably normal

P value = ~0

We reject h0.

type 1 error

Problem 21

We assume the servings were randomly selected. we assume brands are indpendent Nearly normal; NPP is suitably stright

h0: difference=0 ha: diff =/= 0

t=1.33

p value = ~0

reject h0

There is not enough evidence to claim significant difference.