Value of x is used to consider unknown value. The letter “x” is commonly used in algebra to indicate an unknown value. It is referred to as a “variable” or, in some cases, a “unknown.” In x + 2 = 7, x is a variable
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).
7.44-6.26=1.18
1.18 in minutes is 78 minutes bc 1 hour is 60 minutes + 18 minutes is 78
Hope this helps :D
Let x = number of adult tickets sold
Let x-53 = number of student tickets sold
x + x -53 = 697
2x - 53 = 697.
Add 53 to both sides to get:
2x = 750
Divide both sides by 2 to get:
x = 375
375 adult tickets were sold.
7<span>x^4y^6 - Selection 3 is correct!</span>