The valid conclusions for the manager based on the considered test is given by: Option
<h3>When do we perform one sample z-test?</h3>
One sample z-test is performed if the sample size is large enough (n > 30) and we want to know if the sample comes from the specific population.
For this case, we're specified that:
- Population mean =
= $150 - Population standard deviation =
= $30.20 - Sample mean =
= $160 - Sample size = n = 40 > 30
- Level of significance =
= 2.5% = 0.025 - We want to determine if the average customer spends more in his store than the national average.
Forming hypotheses:
- Null Hypothesis: Nullifies what we're trying to determine. Assumes that the average customer doesn't spend more in the store than the national average. Symbolically, we get:

- Alternate hypothesis: Assumes that customer spends more in his store than the national average. Symbolically

where
is the hypothesized population mean of the money his customer spends in his store.
The z-test statistic we get is:

The test is single tailed, (right tailed).
The critical value of z at level of significance 0.025 is 1.96
Since we've got 2.904 > 1.96, so we reject the null hypothesis.
(as for right tailed test, we reject null hypothesis if the test statistic is > critical value).
Thus, we accept the alternate hypothesis that customer spends more in his store than the national average.
Learn more about one-sample z-test here:
brainly.com/question/21477856
x = 8
Solution:
Side-splitter theorem:
<em>If a line is parallel to one side of a triangle and the line intersects the other two sides, then this line divides those two sides proportionally.</em>

Do cross multiplication, we get
⇒ 4 × 42 = 21x
Divide by 21 on both sides, we get
⇒ 4 × 2 = x
⇒ 8 = x
Switch the sides.
⇒ x = 8
The value of x is 8.
Plz mark me as brainliest if this helped :)
well, in order to solve this we can put each marble into a fraction.
so for blue it would be 5 over 15 (5/15)
because there are 15 marbles in the bag but only 5 of them are blue!
but if you need a % then just divide the top by bottom
then you get a 33% chance of picking blue! hope this helps!