Answer:
standard error = 2.11
Step-by-step explanation:
First we stablish the data that we have for each sample:
<u>Population 1</u> <u>Population </u>2
n₁ = 100 n₂ = 90
x¯1= 95 x¯2 = 75
σ₁ = 14 σ₂ = 15
To calculate the standard error of each sample we would use the formulas:
σ = σ₁/√n₁
σx¯2 = σ₂/√n₂
Now, in order to obtain the standard error of the differences between the two sample means we combine those two formulas to obtain this:
σx¯1 - σ x¯2 = √(σ₁²/n₁ + σ₂²/n₂ )
So as you can see, we used the square root to simplify and now we require the variance of each sample (σ²):
σ₁² = (14)² = 196
σ₂² = (15)² = 225
Now we can proceed to calculate the standard error of the distribution of differences in sample means:
σx¯1 - σx¯2 = √(196/100 + 225/90) = 2.11
This gives an estimate about how far is the difference between the sample means from the actual difference between the populations means.
Answer:
c
Step-by-step explanation:
Answer:
<em>A= 1256</em>
Step-by-step explanation:
<u>The formula for area of a circle is </u>
1. Diameter is DOUBLE of radius, so the diameter must be divided by 2. <em>40/2 = 20. </em>
<em>2. </em>Then, plug in the values into the area formula. <em>A= 3.14</em>
3. Solve.<em> A= 1256</em>. (Remember that 20 squared is <em>20x20</em>)
Answer: x = 7.2, y = 7.5
<u>Step-by-step explanation:</u>
Similar triangles have the same proportions.
Since ABC ≅ DEF, then
<u>Let's solve for x:</u>
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<u>Let's solve for y:</u>
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