Answer:
about 3.9 lbs
Step-by-step explanation:
18 7/9 lbs - 14 7/8 lbs
convert mixed numbers to improper fractions
169/9 - 119/8
convert to common denominator
1352/72 - 1071/72
subtract numerators
281/72
about 3.9 lbs
Im not sure if this really helps but I hope it does
Answer:

And replacing we got:

And then the estimator for the standard error is given by:

Step-by-step explanation:
For this case we have the following dataset given:
20.05, 20.56, 20.72, and 20.43
We can assume that the distribution for the sample mean is given by:

And the standard error for this case would be:

And we can estimate the deviation with the sample deviation:

And replacing we got:

And then the estimator for the standard error is given by:
