We can divide 143.50 by 7. This gives us 20.5. This means that she works 20.5 hours a week or 21 hours if you round up.
Answer:
(25.732,30.868)
Step-by-step explanation:
Given that in a random sample of 42 people, the mean body mass index (BMI) was 28.3 and the standard deviation was 6.09.
Since only sample std deviation is known we can use only t distribution
Std error = 

t critical for 99% two tailed 
Margin of error
Confidence interval lower bound = 
Upper bound = 
Step 2: -26.7 · -3
When you divide with a fraction, it's helpful to multiple by the reciprocal of the fraction .
This step instead multiplied by the negative reciprocal .
Therefore, the correct answer would be -80.1 instead of 80.1
The error was made in step 2.
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