Question

The quality manager at Bestiful Company is certifying a new process that must produce 95% (or better) good product before the process is considered proven. A sample of 40 containers from the process line are tested, and 93% are found to be good. (a) Formulate the appropriate hypotheses and test them using an α = 0.01 significance level. (b) Explain your results.

284

likes
1420 views

Answer to a math question The quality manager at Bestiful Company is certifying a new process that must produce 95% (or better) good product before the process is considered proven. A sample of 40 containers from the process line are tested, and 93% are found to be good. (a) Formulate the appropriate hypotheses and test them using an α = 0.01 significance level. (b) Explain your results.

Expert avatar
Dexter
4.7
113 Answers
Let's define the hypotheses for this hypothesis test:
- Null Hypothesis (H0): The proportion of good products produced by the new process is equal to 95%.
- Alternative Hypothesis (H1): The proportion of good products produced by the new process is less than 95%.

Given that the sample size is large (n = 40) and the sample proportion of good products is p̂ = 0.93, we can use the normal approximation to the binomial distribution to conduct a hypothesis test using a z-test.

(a) Test the hypotheses using a significance level of α = 0.01.
The test statistic formula for a z-test is:
z = \frac{p̂ - p}{\sqrt{\frac{p(1-p)}{n}}}
where p is the hypothesized population proportion (0.95 in this case).

Plugging in the values:
z = \frac{0.93 - 0.95}{\sqrt{\frac{0.95(1-0.95)}{40}}}
z = \frac{-0.02}{\sqrt{\frac{0.95*0.05}{40}}}
z = \frac{-0.02}{\sqrt{\frac{0.0475}{40}}}
z = \frac{-0.02}{\sqrt{0.0011875}}
z = \frac{-0.02}{0.03446}
z = -0.58

Next, we find the critical z-value for a one-tailed test at α = 0.01 by looking up the z-value in the standard normal distribution table or using a calculator: z_{\alpha = 0.01} = -2.33

(b) Conclusion:
Since our calculated z-value (-0.58) does not fall in the rejection region (less than -2.33), we do not reject the null hypothesis.
Therefore, there is not enough evidence to conclude that the proportion of good products produced by the new process is less than 95%.

\boxed{Answer: \text{The null hypothesis is not rejected. The process is proven to produce 95\% or more good products.}}

Frequently asked questions (FAQs)
𝑇𝑅𝐴 ≡ 𝑅𝑂𝐵. Find the measure of angle 𝐴𝑇𝑅𝐴.
+
Math question: What is the limit as x approaches 3 of (2x^2 - 9x + 9) / (x - 3)?
+
Math question: In triangle ABC, if the angle bisector of angle A divides the side BC into segments of length 5 and 7, find the length of side BC.
+
New questions in Mathematics
A college believes that 22% of applicants to that school have parents who have remarried. How large a sample is needed to estimate the true proportion of students who have parents who have remarried to within 5 percentage points?
Jose bought 3/4 of oil and his sister bought 6/8, which of the two bought more oil?
A drawer contains three pairs of white socks, five pairs of black socks and two pairs of red socks. Caden randomly selects two pairs of socks on his way to the gym. What is the probability that both pairs of socks are black?
The profit G of the company CHUNCHES SA is given by G(x) = 3×(40 – ×), where × is the quantity of items sold. Find the maximum profit.
Determine the equations of the lines that pass through the following points P1 (2;-1) and p2 (4;-1)
Equivalent expression of the sequence (3n-4)-(n-2)
(2x+5)^3+(x-3)(x+3)
3(2•1+3)4
solve for x 50x+ 120 (176-x)= 17340
Suppose you have a sample of 100 values from a population with mean mu = 500 and standard deviation sigma = 80. Given that P(z < −1.25) = 0.10565 and P(z < 1.25) = 0.89435, the probability that the sample mean is in the interval (490, 510) is: A)78.87% B)89.44% C)10.57% D)68.27%
Two business partners have a bank balance of $17,942.00. After the first year their interest brings their balance to $18,928.91. What rate of interest is earned?
Use a pattern to prove that (-2)-(-3)=1
If a|-7 and a|9, then a|-63
effectiveness of fiscal and monetary policy under closed and open economies
16.What payment (deposit) made at the end of each month will accumulate to $10473 in 13 years at 7.9% compounded monthly? Enter to the nearest cent (two decimals). Do not use $ signs or commas in the answer.
We plan to test whether the mean mRNA expression level differs between two strains of yeast, for each of 8,000 genes. We will measure the expression levels of each gene, in n samples of strain 1 and m samples of strain 2. We plan to compute a P-value for each gene, using an unpaired two-sample t-test for each gene (the particular type of test does not matter). a) What are the null hypotheses in these tests (in words)? [2] b) If, in fact, the two strains are identical, how many of these tests do we expect to produce a P-value exceeding 1/4? [2]
2x-5-x+2=5x-11
Paola went on vacation for 15 days if it rained 20% of the days. How many days did it rain?
The company produces a product with a variable cost of $90 per unit. With fixed costs of $150,000 and a selling price of $1,200 per item, how many units must be sold to achieve a profit of $400,000?
Solve the system of equations by the addition method. 0.01x-0.08y=-0.1 0.2x+0.6y=0.2