What is the range for this set of data? 7,15,12
2 answers:
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Answer:
1. 5000 = N
2. 50 = σ
3. 95% = confidence level (1-α)
4. α = 0.05
5. α/2=0.025=2.5%
6. z_(α/2)=-1.96
1. Width of confidence interval UL-LL=20
Step-by-step explanation:
We have to calculate a 95% confidence interval for the mean (average number of gallons of gas bought per month by the residents of this town).
The margin of error has to be below 10 gallons/month.
The population standard deviation is considered 50 gallons/month.
1. 5000 = N.
This is the population size N for this study, as this is the total population of the town.
2. 50 = σ
This is the value of the population standard deviation σ, as it is estimated from other studies.
3. 95% = (1-α)
This is the confidence level of the interval, and is equal to 1 less the significance level α.
4. α = 0.05
This is calculated from the confidence level. As the confidence level is 95%, the level of significance is 5%.
5. α/2=0.05/2=0.025=2.5%
6. The value os z_α/2 is obtained from a standard normal distribution table, where:
z_α/2=-1.96
1. As the margin of error is 10 (maximum value), the difference between upper and lower bound is: