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A simple random sample of size 
n=14 is obtained from a population with 
mu=69 and 
sigma=16.
(a) What must be true regarding the distribution of the population in order to use the normal model to compute probabilities involving the sample mean? Assuming that this condition is true, describe the sampling distribution of 
bar(x).
(b) Assuming the normal model can be used, determine 
P( bar(x) < 73.4).
(c) Assuming the normal model can be used, determine 
P(x >= 70.7).
(a) What must be true regarding the distribution of the population?
A. Since the sample size is large enough, the population distribution doe need to be normal.
B. The sampling distribution must be assumed to be normal.
C. The population must be normally distributed.
D. The population must be normally distributed and the sample size must be large.
Assuming the normal model can be used, describe the sampling distribution 
bar(x). Choose the correct answer below.
A. Normal, with 
mu_( bar(x))=69 and 
sigma_( bar(x))=16
B. Normal, with 
mu_( bar(x))=69 and 
sigma_( bar(x))=(14)/(sqrt16)
C. Normal, with 
mu_( bar(x))=69 and 
sigma_( bar(x))=(16)/(sqrt14)
(b) 
P( bar(x) < 73.4)= 
◻ (Round to four decimal places as needed.)

A simple random sample of size n=14 n=14 is obtained from a population with μ=69 \mu=69 and σ=16 \sigma=16 .\newline(a) What must be true regarding the distribution of the population in order to use the normal model to compute probabilities involving the sample mean? Assuming that this condition is true, describe the sampling distribution of xˉ \bar{x} .\newline(b) Assuming the normal model can be used, determine P(xˉ<73.4) P(\bar{x}<73.4) .\newline(c) Assuming the normal model can be used, determine P(x70.7) P(x \geq 70.7) .\newline(a) What must be true regarding the distribution of the population?\newlineA. Since the sample size is large enough, the population distribution doe need to be normal.\newlineB. The sampling distribution must be assumed to be normal.\newlineC. The population must be normally distributed.\newlineD. The population must be normally distributed and the sample size must be large.\newlineAssuming the normal model can be used, describe the sampling distribution xˉ \bar{x} . Choose the correct answer below.\newlineA. Normal, with μxˉ=69 \mu_{\bar{x}}=69 and σxˉ=16 \sigma_{\bar{x}}=16 \newlineB. Normal, with μxˉ=69 \mu_{\bar{x}}=69 and μ=69 \mu=69 00\newlineC. Normal, with μxˉ=69 \mu_{\bar{x}}=69 and μ=69 \mu=69 22\newline(b) μ=69 \mu=69 33 μ=69 \mu=69 44 (Round to four decimal places as needed.)

Full solution

Q. A simple random sample of size n=14 n=14 is obtained from a population with μ=69 \mu=69 and σ=16 \sigma=16 .\newline(a) What must be true regarding the distribution of the population in order to use the normal model to compute probabilities involving the sample mean? Assuming that this condition is true, describe the sampling distribution of xˉ \bar{x} .\newline(b) Assuming the normal model can be used, determine P(xˉ<73.4) P(\bar{x}<73.4) .\newline(c) Assuming the normal model can be used, determine P(x70.7) P(x \geq 70.7) .\newline(a) What must be true regarding the distribution of the population?\newlineA. Since the sample size is large enough, the population distribution doe need to be normal.\newlineB. The sampling distribution must be assumed to be normal.\newlineC. The population must be normally distributed.\newlineD. The population must be normally distributed and the sample size must be large.\newlineAssuming the normal model can be used, describe the sampling distribution xˉ \bar{x} . Choose the correct answer below.\newlineA. Normal, with μxˉ=69 \mu_{\bar{x}}=69 and σxˉ=16 \sigma_{\bar{x}}=16 \newlineB. Normal, with μxˉ=69 \mu_{\bar{x}}=69 and μ=69 \mu=69 00\newlineC. Normal, with μxˉ=69 \mu_{\bar{x}}=69 and μ=69 \mu=69 22\newline(b) μ=69 \mu=69 33 μ=69 \mu=69 44 (Round to four decimal places as needed.)
  1. Determine Necessary Condition: Determine the necessary condition for using the normal model for the sample mean. Since the sample size is small n=14n=14, the population must be normally distributed to use the normal model.
  2. Identify Correct Statement: Identify the correct statement about the population distribution. The correct answer is C: The population must be normally distributed.
  3. Describe Sampling Distribution: Describe the sampling distribution of the sample mean xˉ\bar{x}. Since the population is normal, the sampling distribution of the sample mean is also normal. The mean of the sampling distribution is the same as the population mean μ\mu, and the standard deviation of the sampling distribution σxˉ\sigma_{\bar{x}} is the population standard deviation σ\sigma divided by the square root of the sample size nn. Calculation: σxˉ=1614\sigma_{\bar{x}} = \frac{16}{\sqrt{14}}.
  4. Calculate Probability: Calculate the probability P(xˉ<73.4)P(\bar{x} < 73.4) using the normal distribution. Convert 73.473.4 to a z-score: z=73.46916/14z = \frac{73.4 - 69}{16/\sqrt{14}}. Calculate z=1.176z = 1.176. Use the z-table or a calculator to find P(z<1.176)P(z < 1.176).

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