Mr. Quick bought a new computer system. The regular price was $1,580, but he got a 15% discount. How much did he actually pay?
2 answers:
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Answer:
1. The 95% confidence interval for the difference between means is (-5.34, 11.34).
2. The standard error of (x-bar1)-(x-bar2) is 4.
Step-by-step explanation:
We have to calculate a 95% confidence interval for the difference between means.
The sample 1, of size n1=10 has a mean of 45 and a standard deviation of √85=9.2195.
The sample 2, of size n2=12 has a mean of 42 and a standard deviation of √90=9.4868.
The difference between sample means is Md=3.
The estimated standard error of the difference between means is computed using the formula:
The critical t-value for a 95% confidence interval is t=2.086.
The margin of error (MOE) can be calculated as:
Then, the lower and upper bounds of the confidence interval are:
The 95% confidence interval for the difference between means is (-5.34, 11.34).