Classify the following random variable according to whether it is discrete or continuous. The number of players on a football team. 

Identify the level of measurement (nominal, ordinal, interval, ratio) for each of the following variables.  a. Year of Birth  [answera] b. Type of Bird  [answerb] c. Volume of water in a Lake [answerc] d. Rating of a crossword puzzle (easy, medium, hard, expert)  [answerd]

The table below gives the results of a survey given to a random sample of credit card users living in the Los Angeles area.  They were asked their age group and whether or not they pay their credit card balance off in full each month.   Data table Pay off fully each month Do not pay off fully each month Age 20 to 29 years 74 51 Age 30 to 39 years 72 37 Age 40 to 49 years 81 25 Age 50 and older 92 26 Answer the following based on the information in this table.  If rounding is necessary, round to three decimal places.  If a credit card user is randomly selected, what is the probability that they are aged 30 to 39 and do not pay their bill fully each month?  [one] If a credit card user is randomly selected, what is the probability that they are aged 20 to 29 or do not pay off their bill fully each month?  [tw] If a person who does not pay off their bill each month is chosen, what is the probability that they are aged 50 and older? [three]

The table below gives the probability distribution of the number days that workers at a certain company have missed work in the last month.  Data Table Number of Days Missed (x) P(x) 0 0.45 1 0.29 2 0.21 3 ? 4 0.02 Use this table to answer the following. Complete the table by finding P(3).   [answera] Is the random variable, x, discrete or continuous?  [answerb] What is the most likely number of days missed by a worker at this company? If rounding is  necessary, round to two decimal places. [answerc] What is the expected number of days missed by a worker at this company  If rounding is necessary, round to two decimal places. [answerd]  What is the standard deviation in the number of days of work missed by a worker at this company?  If rounding is necessary, round to two decimal places. [answere] Which of the following interpretations of the expected value is correct? [exp]  

Determine whether the sampling is independent or dependent and whether the variable is qualitative or quantitative.  A psychologist wants to measure the effect of music on relaxation.  He random selects 75 volunteers and measures their stress level in silence and then again with the same volunteers the next day while music is playing.   The mean score without music is compared to the mean score with music.

Identify the level of measurement (nominal, ordinal, interval, ratio) for each of the following variables.  a. Temperature of a cup of coffee [cof] b. Height of a 6-year old in inches [hei] c. Color of a car [car] d. Size of a rental car: subcompact, compact, standard, full-size [size]

Which of the following will decrease the width of a confidence interval?

For the​ following, indicate whether a confidence interval for a proportion or mean should be constructed to estimate the variable of interest. Justify your response. Does caffeine intake affect resting heart rate?  A researcher asks 175 women to decrease their caffeine intake by 200 mg per day for two weeks and then records the change in their resting heart rate.  The confidence interval for a [mena] should be constructed because the variable of interest is [var] which is [quant].

A marketing firm wants to compare the proportion of those who say they are regular viewers of reality TV in the 20-29 year and 30-39 year age groups.  In a random sample of 150 people aged 20-29, 49 said they are regular viewers of reality TV.  In a random sample of 200 people aged 30-39, 56 said they are regular viewers of reality TV.  At the 0.05 level of significance test to determine if the proportion is higher in the 20-29 age group.  Assume that the conditions to complete the hypothesis test are met.  1) What is the correct null and alternative hypothesis?  Choose from the options below.  [answer1]                                   a.     H0: 

A survey of 2300 randomly chosen American Adults found that 604 agreed that they had experienced insomnia in the last month.  Use this information to complete the following to find the corresponding 95% confidence interval. a. What is the point estimate of the proportion of American Adults that have experienced insomnia in the last month?  Round to three decimal places.  [answera] b. Does the sample meet the conditions to calculate the confidence interval for the proportion?           [answerb] because the sample is random, the sample is less than 5% of the population and [answerc]. c.  Use the appropriate formula to find the margin of error, rounded to three decimal places.  Remember to round off only at the end.  [answerd] d. Using the margin of error and point estimate from the above questions, find the 95% confidence interval for the proportion of American Adults who have experienced insomnia in the last month.  Round to three decimal places.  Choose the best answer.   [answere]