Answer:
Step-by-step explanation:
You should use the distance formula:
√(2-(-6) squared + 0 - (-5) squared
8 squared + 5 squared = 64+25 = √89
The answer is approximately 9.433
Answer:
the probability that an individual, selected at random, will score below the mean on any normally distributed characteristic is just about 0.5.
Step-by-step explanation:
This probability in normal distribution corresponds to z-score of 0. Using normal distribution tables.
P(z < 0) = 1 - P(z ≥ 0) = 1 - 0.5 = 0.5
Which is very logical, to score below the mean on a normal distribution, the probability is just less than 0.5.
Answer:4
Step-by-step explanation:
Answer:
n=40 boys
Step-by-step explanation:
-Margin of error is given by the formula:
-The z score for a probability of 92% is 1.75
#We make n the subject of the formula and substitute at a 92% confidence:
![E=z\frac{\sigma}{\sqrt{n}}\\\\\sqrt{n}=\frac{z\sigma}{E}\\\\n=[\frac{z\sigma}{E}]^2\\\\\therefore n=[\frac{1.75\times 1.8}{0.5}]^2\\\\=39.69\approx 40](https://tex.z-dn.net/?f=E%3Dz%5Cfrac%7B%5Csigma%7D%7B%5Csqrt%7Bn%7D%7D%5C%5C%5C%5C%5Csqrt%7Bn%7D%3D%5Cfrac%7Bz%5Csigma%7D%7BE%7D%5C%5C%5C%5Cn%3D%5B%5Cfrac%7Bz%5Csigma%7D%7BE%7D%5D%5E2%5C%5C%5C%5C%5Ctherefore%20n%3D%5B%5Cfrac%7B1.75%5Ctimes%201.8%7D%7B0.5%7D%5D%5E2%5C%5C%5C%5C%3D39.69%5Capprox%2040)
Hence, he needs approximately 40 boys for the study
