The compressive strength, in kilopascals, was measured for concrete blocks from five different batches of concrete, both three and six days after pouring. The data are as follows:

a. Construct a 95% confidence interval for the difference between the mean strengths of blocks cured three days and blocks cured six days.

b. A civil engineer claims that the mean strength of blocks cured three days is the same as that of blocks cured six days.
Does the confidence interval contradict this claim?

Transcribed Image Text:

Batch 1 2 3 4 5 After 6 days 1376 1373 1366 1384 1358 After 3 days 1341 1316 1352 1355 1327