18.8 Drove when drinking alcohol. Table 18.7 presented cross-tabulated results for the number of adolescents who drove or rode in a car or other vehicle when the driver was drinking alcohol. Prevalence proportions varied from 11.3% (non-Hispanic white) to 4.9% (non-Hispanic black). Test the data in Table 18.7 for significance by calculating its chi-square statistic, df, and P-value.

Listed below are the lead concentrations in different Ayurveda medicines. Ayurveda is a traditional medical system commonly used in India. The lead concentrations listed here are from medicines manufactured in the United States. Use a significance level to test the claim that the mean lead concentration for all such medicines is less than 14. 3.0,6.5,6.0,5.5,20.5,7.5,12.0,20.5,11.5,17.5

A certain prescription medicine is supposed to contain an average of 250 parts per million (ppm) of a certain chemical. If the concentration is higher than this, the drug may cause harmful side effects; if it is lower, the drug may be ineffective. The manufacturer runs a check to see if the mean concentration in a large shipment conforms to the target level of 250 ppm or not. A simple random sample of 100 portions is tested, and the sample mean concentration is found to be 247 ppm. The sample concentration standard deviation is s = 12 ppm. What are the appropriate null and alternative hypotheses? Group of answer choices H 0:  x̄ = 250 vs. H a:  x̄ < 250 H 0:  x̄ = 250 vs. H a:  x̄ ≠ 250 H 0:  x̄ = 250 vs. H a:  x̄ > 250 H 0: μ = 250 vs. H a:μ < 250 H 0: μ = 250 vs. H a: μ ≠ 250 H 0: μ = 250 vs. H a: μ > 250

A cruise ship charges passengers $3 for a can of soda. Because of passenger complaints, the ship manager has decided to try out a plan with a lower price. He thinks that with a lower price, more cans will be sold, which would mean that the ship would still make a reasonable total profit. With the old pricing, the mean number of cans sold per passenger for a 10-day trip was 10.3 cans. Suppose μ represents the mean number of cans per passenger for the new pricing. What hypotheses should the ship manager test if he wants to determine if the mean number of cans sold is greater for the new pricing plan? O Ho: μ = 10.3 versus H₂: μ> 10.3 O Ho: μ = O Ho: μ = 10 versus Ha: μ 10.3

During a quality assurance check, the actual contents (in grams) of six containers of protein powder were recorded as 1527, 1532, 1504, 1517, 1528, and 1516. (a) Find the mean and the median of the contents. (b) The third value was incorrectly measured and is actually 1520. Find the mean and the median of the contents again. (c) Which measure of central tendency, the mean or the median, was affected more by the data entry error? ..... (a) The mean is (Round to one decimal place as needed.) The median is (Type an integer or a decimal. Do not round.) (b) The mean is (Round to one decimal place as needed.) The median is (Type an integer or a decimal. Do not round.) (c) After correcting the error, the mean by and the median by The was affected more. (Round to one decimal place as needed.)

Choose the appropriate statistical test. When computing, be sure to round each answer as indicated. A dentist wonders if depression affects ratings of tooth pain. In the general population, using a scale of 1-10 with higher values indicating more pain, the average pain rating for patients with toothaches is 6.8. A sample of 30 patients that show high levels of depression have an average pain rating of 7.1 (variance 0.8). What should the dentist determine? 1. Calculate the estimated standard error. (round to 3 decimals). [st.error] 2. What is thet-obtained? (round to 3 decimals). 3. What is the t-cv? (exact value) 4. What is your conclusion? Only type "Reject" or Retain"

A statistician changes her level of significance from .001 to .05.  What impact will this change have on her risk of making a Type I and Type II error?  Is the change in the level of significance a good decision?  Why or why not?

This is about ANOVA: 1. What does one-way mean? 2. What does between-subjects mean? 3. A researcher conducts a one-way ANOVA with four levels. How many different groups are in this study? 4. What are the two sources of variability for the one-way ANOVA?