Answer:
The critical value for a 98% CI is z=2.33.
The 98% confidence interval for the mean is (187.76, 194.84).
Step-by-step explanation:
We have to develop a 98% confidence interval for the mean number of minutes per day that children between the age of 6 and 18 spend watching television per day.
We know the standard deveiation of the population (σ=21.5 min.).
The sample mean is 191.3 minutes, with a sample size n=200.
The z-value for a 98% CI is z=2.33, from the table of the standard normal distribution.
The margin of error is:

With this margin of error, we can calculate the lower and upper bounds of the CI:

The 98% confidence interval for the mean is (187.76, 194.84).
Answer:
2/5
Step-by-step explanation:
Since we have two points on the line, we can use the slope formula
m = ( y2-y1)/(x2-x1)
= ( 7-5)/(9 - 4)
= 2/5
Answer:
598 books
Step-by-step explanation:
Let x be the number of books in the 3rd pile. We will have then:
1st pile: 2x + 10
2nd pile: 2x
3rd pile: x
3000 = (2x + 10) + (2x) + (x)
3000 = 5x + 10
3000 - 10 = 5x
2990 = 5x
2990/5 = x
x = 598 books in the third pile!
We can check that:
3000 = 2*598 + 10 + 2*598 + 598
3000 = 1196 + 10 + 1196 + 598
3000 = 3000 CHECK!
Answer:
x
Step-by-step explanation: