Hi,
Just want to verify my solution.
The average breathalyzer scores for 5 months are given below
12.5
12.6
12.4
13.7
13.3
with a standard deviation of 0.57
Properly calibrated, the machine would give an average reading of 12.3. Should the machine be readjusted at the 90% confidence level?
root(n)= 5^(1/2)= 2.236
Z= (12.9- 12.3) / (0.57/2.236)
Z= 0.60/0.2549
Z= 2.35386
the critical value for 90% confidence is 1.646 so we can conclude that the machine needs some adjustment.
Is this solution correct?
Thanks
Just want to verify my solution.
The average breathalyzer scores for 5 months are given below
12.5
12.6
12.4
13.7
13.3
with a standard deviation of 0.57
Properly calibrated, the machine would give an average reading of 12.3. Should the machine be readjusted at the 90% confidence level?
root(n)= 5^(1/2)= 2.236
Z= (12.9- 12.3) / (0.57/2.236)
Z= 0.60/0.2549
Z= 2.35386
the critical value for 90% confidence is 1.646 so we can conclude that the machine needs some adjustment.
Is this solution correct?
Thanks