We use Minitab 16 Software to solve the problems.
Question #1.
- Find the range, variance and standard deviation of this data set
Descriptive Statistics: NICOTINE
Variable    N  N*    Mean  SE Mean   StDev  Variance  Minimum      Q1  Median
NICOTINE  500   0  0,8425   0,0155  0,3455    0,1194   0,0500  0,7000  0,9000
Variable      Q3  Maximum   Range
NICOTINE  1,1000   1,9000  1,8500
- Create the relative frequency histogram for the nicotine level.
Graph -> Histogram -> With Fit
- Compute the interval y ± 2s
y =0.8425s=0.3455y +2s=0.8425+2*0.3455=1.5335
y -2s=0.8425-2*0.3455=0.1515
Hence, the interval has the following form: (0.1515; 1.5335)
- Estimate the percentage  ...
                                                    
