Answer: B. x ~ B(50, .1)
In other words, it's the second answer choice
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Explanation:
We have n = 50 people in the sample and p = 0.10 is the decimal form of 10%, to represent the probability of success. In this case, we define "success" as "the person passes the fitness test".
The random variable x is the count of how many people pass. So we could have x = 0, x = 1, x = 2, ..., x = 49, x = 50. Basically any whole number from 0 to 50 inclusive. Furthermore, x is approximately modeled by the binomial distribution which we denote as B(n, p) = B(50, 0.1)
So X ~ B(50, 0.1)
Use the FOIL (first, outside, inside, last) to expand the terms in the brackets.
(w - 7)(w + 4)
first: w × w = w²
outside: w × 4 = 4w
inside: -7 × w = -7w
last: -7 × 4 = -28
Now you add all the terms together to get:
w² + 4w - 7w - 28
This simplifies to give you:
w² - 3w - 28
Hope that helps! :)
The decision rule for rejecting the null hypothesis, considering the t-distribution, is of:
- |t| < 1.9801 -> do not reject the null hypothesis.
- |t| > 1.9801 -> reject the null hypothesis.
<h3>What are the hypothesis tested?</h3>
At the null hypothesis, it is tested if there is not enough evidence to conclude that the mean voltage for these two types of batteries is different, that is, the subtraction of the sample means is of zero, hence:

At the alternative hypothesis, it is tested if there is enough evidence to conclude that the mean voltage for these two types of batteries is different, that is, the subtraction of the sample means different of zero, hence:

We have a two-tailed test, as we are testing if the mean is different of a value.
Considering the significance level of 0.05, with 75 + 46 - 2 = 119 df, the critical value for the test is given as follows:
|t| = 1.9801.
Hence the decision rule is:
- |t| < 1.9801 -> do not reject the null hypothesis.
- |t| > 1.9801 -> reject the null hypothesis.
More can be learned about the t-distribution in the test of an hypothesis at brainly.com/question/13873630
#SPJ1
Maybe 430 or 400 could be the answer to that problem