Answer:
P(6) = 0.6217
Step-by-step explanation:
To find P(6), which is the probability of getting a 6 or less, we will need to first calculate two things: the mean of the sample (also known as the "expected value") and the standard deviation of the sample.
Mean = np
Here, "n" is the sample size and "p" is the probability of the outcome of interest, which could be getting a heads when a tossing a coin, for instanc
So, Mean = n × p = (18) ×(0.30) = 5.4
Next we we will find the standard deviation:
Standard Deviation =
n = 18 and p = 0.3 "q" is simply the probability of the other possible outcome (maybe getting a tails when flipping a coin), so q = 1 - p
Standard Deviation =
= 1.944
Now calculate the Z score for 6 successes.
Z = ( of successes we're interested in - Mean) ÷ (Standard Deviation)
=(6-5.4) ÷ (1.944) = 0.309
we have our Z-score, we look on the normal distribution and find the area of the curve to the left of a Z value of 0.309. This is basically adding up all of the possibilities for getting less than or equal to 6 successes. So, we get 0.6217.