Completely lost!
I understand the concept, but I have no clue what’s going on with the table.
Any help/comments would be appreciated.
That table is just your standard (shortened) z-table.
So, as the question gives, mean = 5, variance = 4 (S.D. = 2) and your X = -0.4
Substitute into formula to find z, where z = (Mean - X)/S.D. = [5 - (-0.4)]/2 = 2.7. This means that the value of X is 2.7 S.D. away.
You find 2.70 on the table and you get 0.9965. This means that 99.65% of the observations happen above -0.4. Therefore, 0.35% of the observations occur below -0.4.
excuse me i get the part where we get 99.65% but why is the interpretation above -0.4, i dont seem to get that part :C 1-0.9965 got me lost. the only way i would understand it is with a -2.7 and the graphic backwards so the probability 0.9965 does mean above 0.4, what ur explanaintion of 2.7 confusses me a lot.
question:
A variable is normally distributed with a mean of 5.00 and a variance of 4.00. Using the excerpt above from the cumulative distribution function for the standard normal random variable table, the probability of observing a value of −0.40 or less is closest to: