Confidence Intervals

#1
Can anyone let me know if this sounds right.

A scientist is researching a species of squid. A sample of 25 full grown squid is obtained and the average weight is 652 grams with a standard deviation of 246 grams. Calculate a 90% confidence interval for the population mean weight of full grown squid of this species. (Round to two decimal places)

I got 652+or-1.711x246/square root of 25 = (567.82, 668.84)
We are 90% confident that the population mean weight of full-grown squid of this species is between 567.82grams and 668.84grams.

Does this seem right?
 

JohnM

TS Contributor
#2
Your z score should be 1.645, not 1.711, so that will adjust your answer.

Also - check your arithmetic - I'm not sure how you came up with your answers, even if 1.711 was correct....


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