The conditional relative frequency table was generated using data that compares the number of boys and girls who pack their lunc
2 answers:
You might be interested in
Answer:
a) The sample mean is of 49 and the sample standard deviation is of 11.7.
b) The range of the true mean at 90% confidence level is of 9.62 hours.
c) The prediction interval, at a 90% confidence level, of it's failure time is between 39.38 hours and 58.62 hours.
Step-by-step explanation:
Question a:
Sample mean:
Sample standard deviation:
The sample mean is of 49 and the sample standard deviation is of 11.7.
b)Determine the range of the true mean at 90% confidence level.
We have to find the margin of error of the confidence interval. Since we have the standard deviation for the sample, the t-distribution is used.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 6 - 1 = 5
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 5 degrees of freedom(y-axis) and a confidence level of . So we have T = 2.0.150
The margin of error is:
In which s is the standard deviation of the sample and n is the size of the sample. So
The range of the true mean at 90% confidence level is of 9.62 hours.
(c)If a seventh sample is tested, what is the prediction interval (90% confidence level) of its failure time.
This is the confidence interval, so:
The lower end of the interval is the sample mean subtracted by M. So it is 49 - 9.62 = 39.38 hours.
The upper end of the interval is the sample mean added to M. So it is 49 + 9.62 = 58.62 hours.
The prediction interval, at a 90% confidence level, of it's failure time is between 39.38 hours and 58.62 hours.
Answer:
s ≈ 105
Step-by-step explanation:
<u>Given:</u>
- The data set: 700, 735, 680, 890, 755, 740, 670, 785, 805, 1050, 820, 750
<u>To find:</u>
- The standard deviation of the data
<u>Steps:</u>
To find the standard deviation, first write the computational formula for the standard deviation of the sample.
Take the square root of the answer found in step 7 above. This number is the standard deviation of the sample. It is symbolized by . Here, we round the standard deviation to the nearest whole number.
Rounding to the nearest whole number:
s ≈ 105