The probability that a randomly selected adult has an IQ less than
135 is 0.97725
Step-by-step explanation:
Assume that adults have IQ scores that are normally distributed with a mean of mu equals μ = 105 and a standard deviation sigma equals σ = 15
We need to find the probability that a randomly selected adult has an IQ less than 135
For the probability that X < b;
- Convert b into a z-score using z = (X - μ)/σ, where μ is the mean and σ is the standard deviation
- Use the normal distribution table of z to find the area to the left of the z-value ⇒ P(X < b)
∵ z = (X - μ)/σ
∵ μ = 105 , σ = 15 and X = 135
∴ 
- Use z-table to find the area corresponding to z-score of 2
∵ The area to the left of z-score of 2 = 0.97725
∴ P(X < 136) = 0.97725
The probability that a randomly selected adult has an IQ less than
135 is 0.97725
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Answer:
You need to work 16 more hours to buy a bicycle.
Step-by-step explanation:
199(the cost of the bike) - 55(already have) = 144
144 ÷ 9(earn per hour) = 16
Answer:

Step-by-step explanation:
The confidence interval for the population mean x can be calculated as:

Where x' is the sample mean, s is the population standard deviation, n is the sample size and
is the z-score that let a proportion of
on the right tail.
is calculated as: 100%-99%=1%
So, 
Finally, replacing the values of x' by 308, s by 17, n by 15 and
by 2.576, we get that the confidence interval is:

Answer:

Step-by-step explanation:
Equation: 
1).
→
2).
∴ 
3). 

4). now plug
into 


5). Minimum (0,-5) ∴ 