A psychologist studying the human factors of computer keyboards sets up an experiment to compare two different keyboard designs. He measures the number of words per minute typed by one group on Keyboard A and then he measures the number of words typed per minute by another group of people on Keyboard B. Use the data below to determine if the typing speeds on the two different keyboards are significantly different. Keyboard A (words per minute) 54, 62, 75, 59, 78, 64, 69, 72, 50, 73 Keyboard B (words per minute) 47, 51, 54, 62, 44, 51, 48, 65, 42, 44, 71, 68   Evaluate on a TI 83 calculator

You are an education researcher interested in studying if race or ethnicity affects the severity of punishment children receive.  Through open records, you are able to collect from several high schools the length of suspensions given to kids for fighting along with the race/ethnicity of the child.  The state of Texas divides school children into one of 7 race/ethnicity groups: African American, American Indian, Asian, Hispanic, Pacific Islander, White, or Multiracial.  You want to compare the average length of suspension among these 7 groups.  Which statistical test would be best to determine if there is a significant difference in the severity of punishment among the different groups?     one-sample t-test     related samples t-test     independent samples t-test     ANOVA

The owners of an amusement park count the number of adults and children who attend the park on a Friday and Saturday. The completed table is shown below.    Friday Saturday Total Adults 245 371 616 Children 154 277 431 Total 399 648 1,047 How does the joint frequency for the number of adults who attended the amusement park on Friday compare to the joint frequency for the number of children who attended the amusement park on Saturday?     The joint frequency for the number of adults who attended the amusement park on Friday is 399, which is less than the joint frequency for the number of children who attended the amusement park on Saturday, 431. The joint frequency for the number of adults who attended the amusement park on Friday is 154, which is less than the joint frequency for the number of children who attended the amusement park on Saturday, 277. The joint frequency for the number of adults who attended the amusement park on Friday is 371, which is…

Researchers wanted to know the effectiveness of a new allergy medicine.  A study was conducted on 500 adults who experience allergy symptoms.  Each adult was randomly assigned to receive the new allergy medicine or a placebo.  Researchers recorded whether or not their symptoms improved within 1 week. a.   Complete the two-way table summarizing the findings.   Allergy Medicine Placebo Total Symptoms Improved  85 80   Symptoms DidNot Improve         Total 215    285 500    b.  Use the study results to complete the following.  Round your answer to the nearest tenth of a percent, as needed. Notice the percent sign is already included, so you just need to type the number.  What percent of the adults in this study were given the new allergy medicine?  % What percent of those who experienced improvements received the allergy medicine?   %  What percent of those who received the allergy medicine experienced improvements?   %  What percent of those who did not received the allergy…

A city official would like to know if there is public support for increasing funding for arts programs. To collect data, the city official stands outside a concert hall after a show and surveys every 25th person to exit and asks their opinion about raising funds for the arts. Which of the following describes the population in this scenario? all residents of the city the members of the city council all city residents who support the arts the people surveyed by the city official

A consumer group wanted to determine if there was a difference in customer perceptions about prices for a specific type of toy depending on where the toy was purchased.  In the local area there are three main retailers: W-Mart, Tag, and URToy.  For each retailer, the consumer group randomly selected 5 customers, and asked them to rate how expensive they thought the toy was on a 1-to-10 scale (1= not expensive, to 10 = very expensive). The toy was priced the same at all retail stores. Compute the percentage of variance explained by the group differences for these data. Q: Percentage and variance explained = ?

What proportion of the general population has an IQ of 70 or less?

The council leaders of a small town would like to determine the average number of people living in each household. To accomplish this, they send a questionnaire to each residence listed in the town address records, asking the head of the household to record the number of people living in the dwelling. They follow this up with visits to those households that have not responded to the questionnaire until the data collection process is complete. Which of the following is the best description of the method for data collection used by the council leaders? (A) A convenience sample (B) A simple random sample (C) A stratified random sample (D) A cluster random sample (E) A census

A certain county had a population of 34,485 people. The county hospital is interested in estimating the number of people in the county with blood type-O. To do this, they test blood samples from 228 patients. Out of this group, 10 have blood type-O. Use this sample to estimate the number of people in the county with blood type-O.

A company conducted a marketing survey of its clientele and found that 215 own an iPhone and 106 own an iPad. If 19 clients own both an iPhone and an iPad, how many interviewed have an iPhone or an iPad?