a food snack manufacturer samples 9 bags of pretzels off the assembly line and weights their contents. If the sample mean is 14.
1 answer:
Answer:
<h2>13.7≤Step-by-step explanation:
The formula for calculating the confidence interval is expressed as shown;
CI = xbar ± Z(б/√n)
xbar is the sample mean
Z is the value at 95% confidence interval
б is the standard deviation of the sample
n is the number of samples
Given xbar = 14.2, Z at 95% CI = 1.96, б = 0.70 and n = 9
Substituting this values into the formula;
CI = 14.2 ± 1.96(0.70/√9)
CI = 14.2 ± 1.96(0.70/3)
CI = 14.2 ± 1.96(0.2333)
CI = 14.2 ± 0.4573
CI = (14.2-0.4573, 14.2+0.4573)
CI = (13.7427, 14.6537)
Hence, the 95% confidence interval of the true mean is within the range
13.7≤≤14.7 (to 1 decimal place).
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