The standard iq test is designed so that the mean is 100 and the standard deviation is 15 for the population of all adults. we wish to find the sample size necessary to estimate the mean iq score of all people who have successfully passed a college statistics course. we want to create a confidence interval that is no wider than 8 iq points. the standard deviation for this sub-population is certainly less than 15 as it should be a less variable population. therefore by using σσ = 15 we will obtain a conservative sample size, meaning it will be sufficient large enough. how large a sample should we utilize for a 95% confidence interval? (use the z-score 1.95996 )

55 people is the minimum sample size

Step-by-step explanation:

The formula for minimum sample size is  for µ is:  n = [(z*σ)/E]²

We are given z = 1.95996, σ = 15 and E = 4

E is 4 because they said they want the interval no wider than 8, so that means 4 lower and 4 higher than the mean, so E is 4

Calculate:  n = [(1.95996*15)/4]² = 54.02, we always round up when talking about people.  Since 54.02 is the score, we need more than 54 people, since we can't have parts of a person, we need to round up to 55

c.   x=2.4cm

step-by-step explanation:

similar triangles are triangles which have the same shape but not the same size. this means their angle measures are equal but their side lengths are not instead they are proportional. to solve, we will set up a proportion and solve.

a proportion is two equal ratios set equal to each other. we form the ratios by finding corresponding sides (sides which match to each other on both triangles by their position). out ratios will be one side of the small triangle over the corresponding side on the big triangle as shown below:

.

to solve the proportion, we'll cross multiply by multiplying numerator with denominator across the equal sign.

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step-by-step explanation: