statistics;Question 1;Independent random samples taken on two university campuses revealed the following information concerning the average amount of money spent on non-textbook purchases at the university?s bookstore during the fall semester.;University A;University B;Sample Size;50;40;Average Purchase;$260;$250;Population Standard Deviation(?);$20;$23;We want to determine if, on the average, students at University A spent more on non-textbook purchases at the university?s bookstore than the students at University B.;a. Compute the test statistic.;b. Compute the p-value.;c. What is your conclusion? Let? =.05.;Question 2;In a residual plot against x that does not suggest we should challenge the assumptions of our regression model, we would expect to see;A;a horizontal band of points centered near zero;B;a widening band of points;C;a band of points having a slope consistent with that of the regression equation;d;a parabolic band of points;Question 3;If we are testing for the equality of 3 population means, we should use the;A;test statistic t;B;test statistics z;C;test statistic? 2;d;test statistic F;Question 4;The expected value of mean equals to the mean of the population from which the sample is drawn;A;only if the sample size is 100 or greater;B;for any sample size;C;only if the sample size is 50 or greater;D;only if the sample size is 30 or greater;Question 5;A simple random sample of size n from a finite population of size N is to be selected. Each possible sample should have;A;a probability of 1/n of being selected;B;the same probability of being selected;C;a probability of 1/N of being selected;D;a probability of N/n of being selected;Question 6;Consider the following results for two samples randomly taken from two normal populations with equal variances.;Sample I;Sample II;Sample Size;28;35;Sample Mean;48;44;Population Standard Deviation;9;10;a. Develop a 95% confidence interval for the difference between the two population means.;b. Is there conclusive evidence that one population has a larger mean? Explain.;Question 7;As a general guideline, the research hypothesis should be stated as the;A;null hypothesis;B;hypothesis the researcher wants to disprove;C;alternative hypothesis;D;tentative assumption;Question 8;As the degrees of freedom increase, the t distribution approaches the;A;uniform distribution;B;p distribution;C;exponential distribution;D;normal distribution;Question 9;Two approaches to drawing a conclusion in a hypothesis test are;a;p-value and critical value;B;Type I and Type II;C;one-tailed and two-tailed;D;null and alternative;Question 10;In hypothesis testing, the alternative hypothesis is;A;the maximum probability of a Type I error;B;All of the answers are correct;C;the hypothesis tentatively assumed true in the hypothesis-testing procedure;D;the hypothesis concluded to be true if the null hypothesis is rejected;Question 11;For a two-tailed hypothesis test about?, we can use any of the following approaches except;A;compare the p-value to the value of? (alpha);B;compare the level of significance to the confidence coefficient;C;compare the confidence interval estimate of? to the hypothesized value of?;D;compare the value of the test statistic to the critical value;Question 12;An interval estimate is used to estimate;A;a sample statistic;B;a population parameter;C;the shape of the population's distribution;D;the sampling distribution;Question 13;A small stock brokerage firm wants to determine the average daily sales (in dollars) of stocks to their clients. A sample of the sales for 36 days revealed average daily sales of $200,000. Assume that the standard deviation of the population is known to be $18,000.;a. Provide a 90% confidence interval estimate for the average daily sale.;b. Provide a 99% confidence interval estimate for the average daily sale.;Question 14;An example of statistical inference is;A;descriptive statistics;B;calculating the size of a sample;C;a population mean;D;hypothesis testing;Question 15;If we reject the hypothesis H0:?1 =?2 =?3, we can conclude that;A;all three population means are equal;B;all three population means are different;C;at least two population means are different;D;all three population means are similar;Question 16;In general, higher confidence levels provide;A;a smaller standard error;B;wider confidence intervals;C;narrower confidence intervals;D;unbiased estimates;Question 17;More evidence against H0 is indicated by;A;smaller p-values;B;smaller critical values;C;lower levels of significance;D;lower probabilities of a Type II error;Question 18;The mean of the t distribution is;A;0;B;0.5;C;1;D;a problem specific;Question 19;In a stem-and-leaf display;a;a single digit is used to define each stem, and a single digit is used to define each leaf;B;a single digit is used to define each stem, and one or more digits are used to define each leaf;C;one or more digits are used to define each stem, and one or more digits are used to define each leaf;D;one or more digits are used to define each stem, and a single digit is used to define each leaf;Question 20;In analysis of variance, the levels of the factor are called the;A;experimental units;B;treatments;C;observations;D;dependent variables;Question 21;The weight of a.5 cubic yard bag of landscape mulch is uniformly distributed over the interval from 38.5 to 41.5 pounds.;What is the probability that a bag will weigh less than 41 pounds?;Question 22;In determining an interval estimate of a population mean when? is unknown, we use a t distribution with;A;0 degrees of freedom;B;n? 1 degrees of freedom;C;n degrees of freedom;D;1 degrees of freedom;Question 23;When each data value in one sample is matched with a corresponding data value in another sample, the samples are known as;a;corresponding samples;B;matched samples;C;independent samples;D;None of these alternatives is correct;Question 24;The weekly earnings of fast-food restaurant employees are normally distributed with a mean of $395. If only 10.2% of the employees have a weekly income of more than $422.94, what is the value of the standard deviation of the weekly earnings of the employees?;Question 25;An investment advisor recommends the purchase of shares in Infogenics, Inc. He has made the following predictions;P(Stock goes up 20% | Rise in GDP) =.6;P(Stock goes up 20% | Level GDP) =.5;P(Stock goes up 20% | Fall in GDP) =.4;An economist has predicted that the probability of a rise in the GDP is 20%, whereas the probability of a fall in the GDP is 40%.What is the probability that the stock will go up 20%?;Question 26;A procedure used for finding the equation of a straight line that provides the best approximation for the relationship between the independent and dependent variables is the;A;least squares method;B;mean squares method;C;correlation analysis;D;most squares method;Question 27;An investment advisor recommends the purchase of shares in Infogenics, Inc. He has made the following predictions;P(Stock goes up 20% | Rise in GDP) =.6;P(Stock goes up 20% | Level GDP) =.5;P(Stock goes up 20% | Fall in GDP) =.4;An economist has predicted that the probability of a rise in the GDP is 20%, whereas the probability of a fall in the GDP is 40%.We have been informed that the stock has gone up 20%. What is the probability of a rise or fall in the GDP?
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