Question

3. [3.34/10 Points) DETAILS PREVIOUS ANSWERS DEVORESTAT9 9.E.503.XP. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER The accompanying table gives summary data on cube compressive strength (N/mm) for concrete specimens made with a pulverized fuel-ash mix Sample SD Age (days) 7 Sample Size 68 71 Sample Mean 25.98 35.78 4.84 6.44 28 Calculate a 99% CI for the difference between true average 7-day strength and true average 28-day strength. (Use Hos Hy - H28 = 0. Round your answers to two decimal places.) -12.31 X -7.29 1x ) N/mm² Interpret your 99% CI. With 99% confidence, that the true difference falls below the lower bound. With 99% confidence, that the true difference falls outside these values. . With 99% confidence, we can say that the true difference falls between these values. With 99% confidence, that the true difference falls above the upper bound.

please i need help with this problem
please show all the steps
and formulas.
thank you

Answer 1

From the data given in table 6 = 25.98 68 mi si 4.84 9 - 1,73 h = 71 6.44 11 A 994 CI is given by ac -ġ It Zal S. 2 Sz? 2 Here d = 0.01 d/ -0.005 and Z0005 2.58 0.005 in CI is 25.98 35.78 t (4.842 2.58 Er (6.442 + 68 71 - 9,8 + 2,58 %0.963 9.8 + 2.486 -12-28 -12-286, -7,314 2 decumah 29 ,-9.31) upto (12.29 ）