Answer:
The 80% confidence interval for the the population mean nitrate concentration is (0.144, 0.186).
Critical value t=1.318
Step-by-step explanation:
We have to calculate a 80% confidence interval for the mean.
The population standard deviation is not known, so we have to estimate it from the sample standard deviation and use a t-students distribution to calculate the critical value.
The sample mean is M=0.165.
The sample size is N=25.
When σ is not known, s divided by the square root of N is used as an estimate of σM:

The degrees of freedom for this sample size are:

The t-value for a 80% confidence interval and 24 degrees of freedom is t=1.318.
The margin of error (MOE) can be calculated as:
Then, the lower and upper bounds of the confidence interval are:

The 80% confidence interval for the population mean nitrate concentration is (0.144, 0.186).
Answer: go dnejsheur kejru I didn't do this
Step-by-step explanation:
I think it’s 1/12 exactly you have a one in 12 chances of rolling a 5
X : number of tacos they sell per day. ...... profit = y = 3.25 × x - 210 ......inequality. y > 0. so. x > 210/3.25 = 840/13 = 64. ......so the taco stand must sell at least 65 tacos for making profit.