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2 years ago

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Q. If heights of 3rd graders follow a normal distribution with a mean of 52 inches and a standard deviation of 2.5 inches, what

is the z score of a 3rd grader who is 47 inches tall?
A. z=-5
B. z=-2
C. z=2
D. z=5

1 answer:

zaharov [31]2 years ago

3 0

Answer:

-2

Step-by-step explanation:

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The weather report says the temperature is 20°c and will drop 5°c per hour for the next 6 hours.

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A region R in the xy-plane is given. Find equations for a transformation T that maps a rectangular region S in the uv-plane onto

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The confidence interval for the difference in proportions is

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Step-by-step explanation:

We have to construct a confidence interval for the difference of proportions.

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$p_1-p_2=x_1/n_1-x_2/n_2=(183/217)-(322/398)=0.843-0.809\\\\p_1-p_2=0.034$

The estimated standard error is:

$\sigma_{p_1-p_2}=\sqrt{\frac{p_1(1-p_1)}{n_1}+\frac{p_2(1-p_2)}{n_2} } \\\\\sigma_{p_1-p_2}=\sqrt{\frac{0.843*0.157}{217}+\frac{0.809*0.191}{398} } \\\\\sigma_{p_1-p_2}=\sqrt{0.000609912+0.000388239}=\sqrt{0.000998151} \\\\ \sigma_{p_1-p_2}=0.0316$

The z-value for a 95% confidence interval is z=1.96.

Then, the lower and upper bounds are:

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