Answer:
205.81 to 214.19
Step-by-step explanation:
Sample size (n) = 50
Sample mean weight (X) = 210 grams
Sample standard deviation (s) = 18 grams
Confidence coefficient (Z) at 90% = 1.645
The confidence interval for the true mean breaking strength of cotton threads of this type, at a 90% confidence level, is given by:

The confidence interval is 205.81 grams to 214.19 grams.
Answer: Speed of motorboat= 25 km hr
Speed of current= 5km hr
Step-by-step explanation:
120/4= speed of motorboat with the current
120/6= speed of motorboat against the current
Get the average of those 2 numbers.
Motorboat=25 km hr
Speed of current= 5 km hr
Answer:
at least 290,000
Step-by-step explanation:
Why is this a question
Answer:
Yes
Step-by-step explanation:
They are exact and you can't mess up or accidentally slide the compass or straightedge around. This is just my opinion though.