A sample of n=8 scores has a mean of m=12. What is the value of ∑x for this sample
Answer: We are given the mean of 8 scores is 12.
We are required to find the sum of these 8 observation's, 
We know that:

We are given:




Hence, sum of 8 observation's, 
Answer:
Algebra book weighs 24 oz
Grammar book weighs 15 oz
Step-by-step explanation:
algebra = x and grammar = y
x = 2y-6
5x = 8y
5(2y-6) = 8y
10y - 30 = 8y
2y - 30 = 0
2y = 30
y = 15
x = 2(15)-6
x = 30-6
x = 24
Answer:
x = -10
Step-by-step explanation:
y = 2x + 5
-15 = 2x + 5
-20 = 2x
-10 = x
Answer:
Step-by-step explanation:
Given that: Training-session duration of female rowers with normal iron status is Normally distributed, with mean 69 minutes and standard deviation 18minutes.
Solution:
z score shows the relationship between sample means. The z score is used to determine by how many standard deviations the raw score is above or below the mean. It is given by the formula:

Given that μ = 69 minutes, σ = 18 minutes, n = 24
For x > 63 minutes:

From the distribution table, P(x > 63) = P(z > -1.63) = 1 - P(z < 1.63) = 1 - 0.0516 = 0.9484