taw mass/g 








18.46 








19.24 








19.3 








19.85 








20.12 








20.12 








20.33 








20.35 








20.52 








20.78 








ratio 
1. What level of measurement is the data? 







10 
2. Find the sample size n for the data. 







18.46 
3. Find the minimum. 







20.78 
4. Find the maximum. 







2.32 
5. Find the range. 







20.12 
6. Find the median. 







20.12 
7. Find the mode. 







19.91 
8. Find the sample mean x. 







0.71 
9. Find the sample standard deviation sx. 







0.0356 
10. Find the sample coefficient of variation CV. 







48.82 
11. Determine the zscore for a taw that has a mass of 54.48 grams. 







unusual 
12. Is the zscore above an ordinary or unusual zscore? 







0.22 
13. Calculate the standard error of the mean for the taws. 








14.Calculate the 68% confidence interval for the population mean mass of a taw. 







p( 
19.68 
< μ < 
20.13 
) = 0.68 













Are the taws actually normally distributed? 




Bins 
Freq 
Rel Freq 

18.92 
1 
0.1 

19.39 
2 
0.2 

19.85 
1 
0.1 

20.32 
2 
0.2 

20.78 
4 
0.4 


10 
1 





No, the taws are distributed strongly 



skewed left and bimodally 







Clue to the skew: 



When the mean ≠ median, a skew is present 







Skewness 
0.97 


The skew function is a formula for calculating the skew in the data. The negative, nonzero value 








is a left skew as seen in the diagram. 








Less massive ("lighter") taws are unusual 







