Jenny bought a blanket that was on sale for 25% off. She used a coupon for an additional 15% off any item. After the two discoun
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Answer:
The 98% confidence interval for the variance in the pounds of impurities would be .
Step-by-step explanation:
1) Data given and notation
represent the sample variance
s=4 represent the sample standard deviation
represent the sample mean
n=20 the sample size
Confidence=98% or 0.98
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population mean or variance lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
The Chi square distribution is the distribution of the sum of squared standard normal deviates .
2) Calculating the confidence interval
The confidence interval for the population variance is given by the following formula:
On this case the sample variance is given and for the sample deviation is just the square root of the sample variance.
The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:
Since the Confidence is 0.98 or 98%, the value of and
, and we can use excel, a calculator or a table to find the critical values.
The excel commands would be: "=CHISQ.INV(0.01,19)" "=CHISQ.INV(0.99,19)". so for this case the critical values are:
And replacing into the formula for the interval we got:
So the 98% confidence interval for the variance in the pounds of impurities would be .
Answer:
2236.77 feets
Step-by-step explanation:
From the attached picture, we are to find x, which is the vertical depth of the submarine.
Using trigonometry based on the illustration in the diagram:
Sinθ = opposite / hypotenus
Sinθ = x (depth of submarine) / distance from ship (4000)
Hence,
Sinθ = x / 4000
θ = 34°
Sin34 = x / 4000
0.5591929 * 4000 = x
2236.7716 = x
Hence, depth of submarine = 2236.77 feets
