Salmon Weights (Raw Data, Software Required): construct a 95% confidence interva

ID: 3326134 • Letter: S

Question

Salmon Weights (Raw Data, Software Required): construct a 95% confidence interval for the mean weight of all spawning Chinook salmon in the Columbia River directly from the table into your software program. Columbia river are normally distributed. You randomly catch and weigh 15 such salmon. The data is found in the table below, You want to You will need software to answer these questions. You should be able to copy the data (a) What is the poi nt estimate for the mean weight of all spawning Chinook salmon in the Columbia River? Round your answer to 2 decimal places. Salmon pounds 26.2 25.3 36.5 (b) Construct the 95% confidence interval for the mean weight of all spawning Chinook salmon in the Columbia River. Round your answers to 2 decimal places. 19.4 (c) Are you 95% confident that the mean weight of all spawning Chinook salmon in the Columbia River is greater than 24 pounds and why? No, because 24 is above the lower limit of the confidence interval. Yes, because 24 is below the lower limit of the confidence interval. No, because 24 is below the lower limit of the confidence interval. Yes, because 24 is above the lower limit of the confidence interval. 33.7 26.3 24.0 27.3 33.0 28.2 29.3 28.8 12 13 14 15 (d) Recognizing the sample size is less than 30, why could we use the above method to find the confidence interval? Because the parent population is assumed to be normally distributed. Because we do not know the distribution of the parent population Because the sample size is greater than 10. Because the sample size is less than 100 32.0

Explanation / Answer

Answers:

Part a

Point estimate for mean weight = Sample mean = 28.01

Part b

We have to compute confidence interval by using software.

Required confidence interval by using excel is given as below:

Confidence Interval Estimate for the Mean

Data

Sample Standard Deviation

4.454446681

Sample Mean

28.00666667

Sample Size

Confidence Level

95%

Intermediate Calculations

Standard Error of the Mean

1.150133188

Degrees of Freedom

t Value

2.1448

Interval Half Width

2.4668

Confidence Interval

Interval Lower Limit

25.54

Interval Upper Limit

30.47

25.54 < µ < 30.47

Part c

Answer:

No, because 24 is above the lower limit of the confidence interval.

(For the above confidence interval, 24 is greater than lower limit 25.54.)

Part d