In a sample of 42 water specimens taken from a construction site, 26 contained detectable levels of lead. construct 90% confidence interval for the proportion of water specimens that contain detectable levels of lead.

(0.4958, 0.7422)

Step-by-step explanation:

Let p be the true proportion of water specimens that contain detectable levels of lead. The point estimate for p is . The estimated standard deviation is given by . Because we have a large sample, the 90% confidence interval for p is given by where is the value that satisfies that above this and under the standard normal density there is an area of 0.05. So, the confidence interval is , i.e., (0.4958, 0.7422).

6 cm

step-by-step explanation:

the number of possible outcomes that do not show a 1 on the first spinner and show the number 4 on the second spinner is 2.

spinner 1 spinner 2

1                     1

1                     2

1                     3

1                     4

2                   1

2                   2

2                   3

2                   4   = not 1, and 4

3                   1

3                   2

3                   3

3                   4 = not 1, and 4

only 2 outcomes have passed the given condition.

step-by-step explanation: