Question

this winters snowfall appears to be setting all kind of records - all being low. there was less than 42 cm of snow last month. i looked at the history for oshawa and found that on average, the snow fall in february is 55.8 cm with a standard deviation of 7.5 cm. if one assumes that the. snow fall depths in oshawa over the years follow a normal distribution, it is unusual to have a february monthly snowfall less than 42 cm?

prepare the pdf for this question

perform the test

state your interpretation

Answer 1

µ =    55.8              
σ =    7.5              
left tailed                  
X ≤    42              
                  
Z =   (X - µ ) / σ =   -1.84          
                  
P(X ≤   42   ) = P(Z ≤   -1.84   ) =   0.0329 [excel formula =normsdist(-1.84)

since, probability is less than 0.05, so it is unusual to have a february monthly snowfall less than 42 cm