Question

An industrial plant claims to discharge no more than 1000 gallons of wastewater per hour, on the average, into a neighboring lake. An environmental action group decides to monitor the plant, in case this limit is being exceeded. A random sample of 42 hours is selected over a period of a month. The data are unimodal and roughly symmetric. R 1123, s- 688, and Standard Error 106.161 (a) Using StatCrunch, the p-value (3 decimal places) (b) Are the conditions met to conduct this test? O Yes, because the data are approximately normal O Yes, x-bar is nearly normal because n > 30. Therefore, the Central Limit Theorem can be used Yes, np and n(1-p) are both> 15 O Yes, because the population is approximately normal because n > 30 ONo, np and n(1-p) are not both>15. (c) At alpha 0.05, which of the following is the correct conclusion? Do not reject the null hypothesis. There is evidence that the wastewater discharged by the industrial plant exceeds 1000 gallons per hour. O Do not reject the null hypothesis. There is insufficient evidence that the wastewater discharged by the industrial plant exceeds 1000 gallons per hour. O Reject the null hypothesis. There is sufficient evidence that the wastewater discharged by the industrial plant exceeds 1000 gallons per hour. O Reject the null hypothesis. There is insufficient evidence that the wastewater discharged by the industrial plant exceeds 1000 gallons per hour.

Answer 1

null hypothesis: 1000 Alternate Hypothesis: 1000 for 0.05 level with right tailed test and n-1-41 degree of freedom, critical value of t 1.683 Decision rule: reject Ho if test statistic t>1.683 population mean 1000 sample mean 1123.000 sample size 42.00 n= sample std deviation 688.000 S= standard errror of mean Sx s/Vn= 106.1607 (x-H)/s test statistic t 1.159 p value 0.1267 -

a)

p value =0.127

b)

yes , x-bar is nearly normal because n>30. therefore the central..........

c)

do not reject the null, there is insufficient evidence,,,,,,,,,,,,,,