The output voltage for a certain electric circuit is specified to be 230. A sample of 40 independent readings on the voltage for this circuit gave a sample mean of 228.6 and a standard deviation of 2.1. Test the hypothesis that the average output voltage is 230 against the alternative that it is less than 230. Use a 5% significance level.

Currently patrons at the library speak at an average of 66 decibels. Will this average decline after the installation of a new computer plug in station? After the plug in station was built, the librarian randomly recorded 66 people speaking at the library. Their average decibel level was 63.2 and their standard deviation was 18. What can be concluded at the the a = 0.10 level of significance? a. For this study, we should use Select an answer b. The null and alternative hypotheses would be: Ho: ?v Select an answer v Hị: Select an answer c. The test statistic ? v (please show your answer to 3 decimal places.) d. The p-value = (Please show your answer to 4 decimal places.) e. The p-value is ? va f. Based on this, we should Select an answer g. Thus, the final conclusion is that ... | the null hypothesis. OThe data suggest that the population mean decibal level has not significantly decreased from 66 at a = 0.10, so there is statistically insignificant evidence to conclude that the…

The mean number of eggs per person eaten in the United States is 223. Do college students eat a different number of eggs than the average American? The 51 college students surveyed averaged 237 eggs per person and their standard deviation was 39.3. What can be concluded at the a = 0.01 level of significance? %3D a. For this study, we should use Select an answer b. The null and altemative hypotheses would be: H 2 Select an answer v H 2vSelect an answer v c. The test statistic ? (please show your answer to 3 decimal places.) d. The p-value = (Please show your answer to 4 decimal places.) e. The p-value is | ? v a f. Based on this, we should Select an answer V the null hypothesis. g. Thus, the final conclusion is that... O The data suggest that the populaton mean is significantly different from 223 at a = 0.01, so there is statistically significant evidence to conclude that the population mean number of eggs consumed by college students per year is different from 223. Toctor O The data…

Consider a set of data in which the sample mean is 30.230.2 and the sample standard deviation is 7.87.8. Calculate the z-score given that x=31.4x=31.4. Round your answer to two decimal places.

A fruit grower wants to test a new spray that a manufacturer claims will reduce the loss due to insect damage. She sprays 20 trees with the new spray and 20 trees with the standard spray.  The following data were recorded:   New Spray Standard Spray Mean yield per tree(lb) 240 227 Standard deviation 31.3 28.6   Do the data provide evidence that the new spray increases the yield per tree?

In 16 women with diabetes, the morning blood sugar mean was 49.4  with a standard deviation of 24.0. In normal healthy women, the mean was 47.0. From the sample information, can we conclude that the blood sugar mean in women with rheumatoid arthritis is greater than that in normal women? Assume a significance level of 0.05.

A newspaper article noted that the mean life span for 35 male symphony conductors was 73.2   years with a standard deviation of 8.7 . Males in the general population have a mean life span of 69.5 years. Use a 0.05 significance level to test the claim that male symphony conductors have a mean life span that is greater than 69.5 years. a. Define the parameter     A. mu   ​= The mean life span of the 35 male symphony conductors in the sample   B. p​ = The proportion of all male symphony conductors who life more than 69.5 years   C. mu   ​= The mean life span of all male symphony conductors   D. mu   ​= The mean life span of all males   b. State the null and alternative hypotheses     A. Upper H 0 : mu equals 73.2    Upper H 1 : mu greater than 73.2     B. Upper H 0 : mu equals 69.5 Upper H 1 : mu greater than 69.5     C. Upper H 0 : mu greater than 69.5 Upper H 1 : mu equals 69.5     D. Upper H 0…

Steve believes that his wife's cell phone battery does not last as long as his cell phone battery. On eight different occasions, he measured the length of time his cell phone battery lasted and calculated that the mean was 19.7 hours with a standard deviation of 9.4 hours. He measured the length of time his wife's cell phone battery lasted on twelve different occasions and calculated a mean of 18.9 hours with a standard deviation of 5.3 hours. Assume that the population variances are the same. Let Population 1 be the battery life of Steve's cell phone and Population 2 be the battery life of his wife's cell phone. Step 1 of 2: Construct a 90 % confidence interval for the true difference in mean battery life between Steve's cell phone and his wife's. Round the endpoints of the interval to one decimal place, if necessary.

In a random sample of 6 cell phones, the mean full retail price was 517.30 and standard deviation is 184.00. Further research suggests that the population mean is 425.73. Does the t-value for the original sample fall between -t0.99 and t0.99?