45 + 32n simpllified
1 answer:
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Answer:
a) 0.71
b) 0.9863
Step-by-step explanation:
a. Given the mean prices of a house is $403,000 and the standard deviation is $278,000
-The probability the probability that the selected house is valued at less than $500,000 is obtained by summing the frequencies of prices below $500,000:
Hence, the probability of a house price below $500,000 is 0.71
b. -Let X be the mean price of a randomly selected house.
-Since the sample size 40 is greater than 30, we assume normal distribution.
-The probability can therefore be calculated as follows:
Thus, the probability that the mean value of the 40 houses is less than $500,000 is 0.9863
Answer:
And the 96% confidence is given by (110.06; 117.34)
Step-by-step explanation:
Information given
represent the sample mean
population mean (variable of interest)
s=9.1 represent the sample standard deviation
n=29 represent the sample size
Confidence interval
The confidence interval for the mean is given by the following formula:
(1)
The degrees of freedom are given by:
The Confidence is 0.96 or 96%, the significance is and
, and the critical value would be
Replacing the info we got:
And the 96% confidence is given by (110.06; 117.34)