I would assume that you convert 2.5 ounces into punds which would make it 0.15 lbs.
Let's call our estimate x. It will be the average of n IQ scores. Our average won't usually exactly equal the mean 97. But if we repeated averages over different sets of tests, the mean of our estimate the average would be the same as the mean of a single test,
μ = 97
Variances add, so the standard deviations add in quadrature, like the Pythagorean Theorem in n dimensions. This means the standard deviation of the average x is
σ = 17/√n
We want to be 95% certain
97 - 5 ≤ x ≤ 97 + 5
By the 68-95-99.7 rule, 95% certain means within two standard deviations. That means we're 95% sure that
μ - 2σ ≤ x ≤ μ + 2σ
Comparing to what we want, that's means we have to solve
2σ = 5
2 (17/√n) = 5
√n = 2 (17/5)
n = (34/5)² = 46.24
We better round up.
Answer: We need a sample size of 47 to be 95% certain of being within 5 points of the mean
Answer:
1/3
Step-by-step explanation:
360/120=3
Answer:
Step-by-step explanation:
Step 1: Identify the variables. ...
Step 2: Determine the variable range. ...
Step 3: Determine the scale of the graph. ...
Step 4: Number and label each axis and title the graph.
Step 5: Determine the data points and plot on the graph. ...
Step 6: Draw the graph.
-5(a + 3) = -55
(a + 3)(-5) = -55
(a + 3) (-5)/-5 = -55/ (-5)
a + 3 = 11
a + 3 (-3) = 11 (-3)
a = 8
hope this helps
