Answer:
Step-by-step explanation:
We want to determine a 98% confidence interval to estimate the true mean shear strength of anchor bolts.
Number of sample, n = 78
Mean, u = 4.25
Standard deviation, s = 1.3
For a confidence level of 98%, the corresponding z value is 2.33.
We will apply the formula
Confidence interval
= mean ± z × standard deviation/√n
It becomes
4.25 ± 2.33 × 1.3/√78
= 4.25 ± 2.33 × 0.147
= 4.25 ± 0.34
The lower end of the confidence interval is 4.25 - 0.34 = 3.91
The upper end of the confidence interval is 4.25 + 0.34 = 4.59
b) the confidence interval would still be valid because the number of samples is large(> 30)
Answer:
4
Step-by-step explanation:
4 squared equals 16 and 4 times 4 equals 16
Step-by-step explanation:
5x^2 - 20x + 20 = 5x^2 - 20x + 20
5(x^2 - 4x + 4) = 5(x^2 - 4x + 4)
(5 + 5) (x^2 - 4x + 4)
Hello!
Unit rates can be written as ratios. In this case, we have 4 bushels in one hour, or 4:1. In eight hours, we can multiply like a fraction, multiplying both by eight to get eight hours.
Our final answer is B) 8·4.
I hope this helps!
