A new catalyst is being investigated for use in the production of a plastic chemical. Ten batches of the chemical are produced. The mean yield of the 10 batches is 72.5% and the standard deviation is...

Q1: 12   (Exercise for Section 5.2)

1. In a random sample of 150 customers of a high-speed internet provider, 63 said that their service had been interrupted one or more times in the past month.


2. Find a 95% confidence interval for the proportion of customers whose service was interrupted one or more times in the past month.


3. Find a 99% confidence interval for the proportion of customers whose service was interrupted one or more times in the past month.


4. Find the sample size needed for a 95% confidence interval to specify the proportion to within ± 0.05


5. Find the sample size needed for a 99% confidence interval to specify the proportion to within±0.05.

1. A broth used to manufacture a pharmaceutical product has its sugar contents, in mg/mL ,measured several times on each of three successive days.

Day 1: 5.0  4.8  5.1  5.1  4.8  5.1  4.8  4.8  5.0  5.2  4.9  4.9  5.0

Day 2: 5.8  4.7  4.7  4.9  5.1  4.9  5.4  5.3  5.3  4.8  5.7  5.1  5.7

Day 3: 6.3  4.7  5.1  5.9  5.1  5.9  4.7  6.0  5.3  4.9  5.7  5.3  5.6

1. Can you conclude that the variability of the process is greater on the second day than on the first day?


2. Can you conclude that the variability of the process is greater on the third day than on the second day?