Answer:
The 95% confidence interval for mean compressive strength is:

Step-by-step explanation:
We have a sample of n=12 specimens, with sample mean=3259.9 and sample standard deviation = 35.57.
We know the population is normally distributed.
For a 95% confidence interval and df=n-1=11, the t-statistic is t=2.201.
Then, the CI can be expressed as:

6x^2+14x-12 is the answer
Answer:
the answer is 1.6 seconds
Step-by-step explanation:
I think the answer is 1/m^18
3=a
Subtract a from both sides
18=6a
Then divide six on each side
3=A