The average breaking force of a certain type of fiber must be greater than 200 pounds per square inches (lppc). Previous experiments have shown that we can assume that the breaking force is normally distributed with a standard deviation σ = 4.5 lppc. A sample of 8 fibers gave the following breaking forces (in lppc): 210, 206, 198, 202, 201, 198, 199, 205.
(a) Formulate a null hypothesis against alternative hypothesis to verify that this type of fiber is acceptable.
(b) Calculate the observed value of the test statistic to test the hypotheses of part (a).
(c) Based on the value of the test statistic in part (a): (i) give the conclusion to α = 5%; (ii) give the conclusion to α = 10%.
(d) Suppose that a sample of 30 fibers gives an average breaking force of ¯x = 202, 375 CFPA. For this new study, calculate the observed value of the test statistic for test the hypotheses in part (a) and give the conclusion to α = 5%.
The average breaking force of a certain type of fiber must be greater than 200 pounds...
A local police force must pay for their uniforms at an average cost of $165 allowing for cost variations for size, rank, etc. Switching to a new company reduced the average cost to $149 with a σn-1 = $68.15 based on a sample of n = 42 officers. Perform a hypothesis test with α = 5% to verify if uniform costs have significantly been reduced. A. What is H0? B. What is H1? C. What is the value of the...
Lightbulbs of a certain type are advertised as having an average lifetime of 750 hours. The price of these bulbs is very favorable, so a potential customer has decided to go ahead with the purchase arrangement unless it Can be conclusively demonstrated that the true lifetime is smaller than what is advertised. A random sample of 60 bulbs was selected. In the sample, the mean lifetime was 741.8 and the standard deviation was 19.2. What conclusion would be appropriate for...
The desired percentage of Sio2 in a certain type of aluminous cement is 5.5. To test whether the true average percentage is 5.5 for a particular production facility, 16 independently obtained samples are analyzed Suppose that the percentage of SiO2 in a sample is normally distributed with ơ=0.32 and that x̅=5.21. (Use α-0.05.) (a) Does this indicate conclusively that the true average percentage differs from 5.5? State the appropriate null and alternative hypotheses Calculate the test statistic and determine the P-value.State the...
Question 7 The mean breaking strength of yarn used in manufacturing drapery material is required to be more than 100 psi. Past experience has indicated that the standard deviation of breaking strength is 2.9 psi. A random sample of 9 specimens is tested, and the average breaking strength is found to be 100.6 psi. Statistical Tables and Charts (a) Calculate the P-value. Round your answer to 3 decimal places (e.g. 98.765). If a = 0.05, should the fiber be judged...
The desired percentage of SiO2 in a certain type of aluminous cement is 5.5. To test whether the true average percentage is 5.5 for a particular production facility, 16 independently obtained samples are analyzed. Suppose that the percentage of SiO2 in a sample is normally distributed with σ = 0.30 and that x= 5.23. (Use α-0.05.) (a) Does this indicate conclusively that the true average percentage differs from 5.5? State the appropriate null and alternative hypotheses Hai μ < 5.5...
To obtain information on the corrosion-resistance properties of a certain type of steel conduit, 40 specimens are buried in soil for a 2-year period. The maximum penetration (in mils) for each specimen is then measured, yielding a sample average of 48.7 and a sample standard deviation of 5.6. The specifications require that the true average penetration should be lesser than 50 mils. Write down the null and alternative hypotheses to be tested. Clearly define the terms used. What is the...
Hypothesis Testing_03 (two independent samples) m the detection temperature under load for two different vnes of plastie pipe is being investee samples of 15 pipe specimens are tested and the detection temperatures observed are as follows ( 7) Type_01: 193 207 206 210 205187194 178 205 185 189213192 188 194 Type_02: 176 180 185 200 197 192 198 177 188 197 189 206 201 203192 a. Write down the null and alternative hypotheses to test if the deflection temperature under...
The desired percentage of SiO2 in a certain type of aluminous cement is 5.5. To test whether the true average percentage is 5.5 for a particular production facility, 16 independently obtained samples are analyzed. Suppose that the percentage of SiO2 in a sample is normally distributed with σ = 0.32 and that x = 5.22. (Use α = 0.05.) (a) Does this indicate conclusively that the true average percentage differs from 5.5? State the appropriate null and alternative hypotheses. H0:...
3. Do you see any striking difference between problem 1 and 2? At a certain university, the mean income of parents of the entering class is reported to by $91,600. The president of another university feels that the parents’ income for her entering class is more than $91,600. She surveys 100 randomly selected families and finds the mean income to be $96,321. Given σ = $9555. With α = 0.05, is she correct? State the null and alternative hypotheses which...
.A sample of 200 individuals are tested for their blood type is given in the first table, and the results are used to test the hypothesized distribution of blood types. The observed results are given in the second table. At the .05 level of significance, is there sufficient evidence to show that the stated distribution is incorrect? Blood Type A B O AB Percent 0.41 0.06 0.41 0.12 Blood Type A B O AB Number 73 17 84 26 (a)...