A researcher wants to determine a model to predict the 28-day strength of a concrete mixture. The following data represent the slump (a measure of concrete uniformity in inches) x1, 7-day strength (in pounds per square inch, or psi) x2, and the 28-day strength (in psi) y of a certain type of concrete. Slump measure of the uniformity of the concrete, with a higher slump indicating a less uniform mixture. Complete parts x1 3.75 4.5 2.5 4 3 2.5 4.5 4.25
х2 3080 1770 2050 3360 2250 2240 2640 3810 3350 3875 4025
y 3890 3765 4985 4475 3610 4535 2590 2220 2510 2330 4685

Construct 95% confidence and prediction intervals for concrete for which slump is 3.0 inches and 7-day strength is 2600 psi. Interpret the results.

Find the 95% confidence interval for the sample.

lower bound =
upper bound = (Round to one decimal place as needed.)

Find the 95% prediction interval for the sample.

lower bound =
upper bound = (Round to one decimal place as needed.)

Based on these results, it can be said with 95% confidence that the 28-day strength for a specific sample of concrete for which slump is 3.0 inches and 7-day strength is 2600 psi will be between about psi and the mean 28-day strength of all concrete for which slump is 3.0 inches and 7-day strength is 2600 psi will be between about psi.