Question

Strength of concrete: 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. Can you conclude that the mean strength after three days is greater than the mean strength after six days? Let μ1 represent the mean strength after three days and =μd−μ1μ2. Use the =α0.01 level and the P-value method with the TI-84 Plus calculator.

Block

1. 2 3. 4. 5

After 3 days 1364 1320 1366 1341 1364

After 6 days 1342 1330 1325 1322 1341

a) State the null and alternate hypotheses.

b) p-value

c) reject or not

d) state conclusion

Answer 1