our company wants to improve sales. Past sales data dicate that the average sale was $200 per transaction. fter training your sales force, recent sales data (taken from sample of 9 sales reps) indicates an average sale of $250, with a standard deviation of s = $36. Did the training work? ou will conduct a one sample t-test with alpha = 0.01, one ailed, to determine whether the average sale significantly creased from $200 (that is, Ho is that the sales do not differ gnificantly from $200, and H₁ is that ney significantly increased).

A certain breed of rat shows a mean weight gain of 65g during the first 3 months of life. A random sample of 34 rats of this breed are fed a new diet from birth until age 3 months. These 34 rats have a mean weight gain of 60.75g and a standard deviation of 3.84g. We are interested in testing whether there is reason to believe, at the 0.05 significance level, that the new diet is causing a change in the average amount of weight gained in this breed of rats. By comparing the test statistic and the critical value, what conclusion can we draw at the 0.05 significance level? Since the test statistic is more extreme than the critical value, we reject the null hypothesis. We have statistically significant evidence to conclude that average weight gain during the first 3 months of a certain breed of rat's life on the new diet is not equal to 65g. Since the test statistic is NOT more extreme than the critical value, we fail to reject the null hypothesis. We do not have statistically significant…

What is the critical value of a one-tailed greater than One-Sample Z-Test for Mean where alpha equals 0.05?

If we conduct a z-test and use the alpha level of p < .05 [and our test is 'non directional,' i.e, we consider values at both ends of the z-score distribution] the value that we calculate for the z-test has to fall inside                                 to be considered rare enough to be statistically significant.     5% of the lower values (tail of the curve) or 5% of the upper values in the other tail of the curve.     The middle 5% of the curve     2.5% of the lower values (tail of the curve) or 2.5% of the upper values in the other tail of the curve.     The middle 95% of the curve

What is the critical value at an alpha of .01 as a 1-tailed test, and based on its calculation what should the decision be? What is the possible error made? Was there an error?

Recently, a simple random sample of 572 adult males showed that 124 of them smoke. It has been established that in 2008. 20.4% of adults smoke. Use a 0.05 significance level to test the claim that the rate of smoking by adult males is now the same as in 2008. What is the value of the critical z tabular value?

Before the furniture store began its ad campaign, it averaged 158 customers per day. The manager is investigating if the average is smaller since the ad came out. The data for the 11 randomly selected days since the ad campaign began is shown below:  147, 142, 149, 133, 146, 159, 132, 137, 148, 172, 150 Assuming that the distribution is normal, what can be concluded at the αα = 0.10 level of significance? For this study, we should use Select an answer z-test for a population proportion t-test for a population mean  The null and alternative hypotheses would be:       H0:H0:  ? μ p  Select an answer > ≠ < =         H1:H1:  ? p μ  Select an answer < ≠ > =     The test statistic ? z t  =  (please show your answer to 3 decimal places.) The p-value =  (Please show your answer to 4 decimal places.) The p-value is ? ≤ >  αα Based on this, we should Select an answer accept fail to reject reject  the null hypothesis. Thus, the final conclusion is that ... The data suggest…

According to the Oxnard College Student Success Committee report in the previous year, we believe that 17% of students struggle in their classes because they don't spend more than 8 hours studying independently outside of a 4-unit class. For this year, you would like to obtain a new sample to estimate the proportiton of all Oxnard students who struggle in their classes because they don't study enough outside of the classrooms. You would like to be 95% confident that your estimate is within 1% of the true population proportion. How large of a sample size is required? Do not round mid-calculation. n =

An airline company is interested in improving customer satisfaction rate from the 66% currently claimed. The company sponsored a survey of 262 customers and found that 184 customers were satisfied. What is the test statistic z? What is the p-value? Does sufficient evidence exist that the customer satisfaction rate is higher than the claim by the company at a significance level of α=0.01 (Y/N)

Twenty-two young asthmatic volunteers were studied to assess the short-term effects of sulfur dioxide (SO2) exposure under various conditions [12]. The baseline data in Table 12.30 were presented regarding bronchial reactivity to SO2 stratified by lung function (as defined by forced expiratory volume / forced vital capacity [FEV1/FVC]) at screening. *12.6 Test the hypothesis that there is an overall mean difference in bronchial reactivity among the three lung-function groups. *12.7 Compare the means of each pair of groups using the LSD method. *12.8 Compare the means of each pair of groups using the Bonferroni method.