Blog

Suppose 10% of all people who shop at Conrads bookstore buy an OSU t-shirt.  If we select 15 random people who shopped at Conrads last week, what is the probability that exactly 2 of them purchased an OSU t-shirt? Report 4 decimal places in your answer

Examine the Cereal dataset in the Lock5Data package. A model was fit to predict Calories based on the amount of sugar in the cereal and the following output was generated. Call:lm(formula = Calories ~ Sugars, data = Cereal) Residuals:Min            1Q            Median         3Q           Max -36.574   -25.282        -2.549       17.796      51.805 Coefficients:                    Estimate       Std. Error         t value            Pr(>|t|) (Intercept)     88.9204         10.8120           8.224            5.96e-09 ***Sugars            4.3103           0.9269           4.650            7.22e-05 ***—Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 Residual standard error: 26.61 on 28 degrees of freedomMultiple R-squared: 0.4357, Adjusted R-squared: 0.4156 F-statistic: 21.62 on 1 and 28 DF, p-value: 7.217e-05 What percent of the variability in Calories is explained by Sugars? Report your answer to 4 decimal places

When another predictor is added to a model, the unadjusted R2 can NEVER decrease.

Using the nycflights13 data. I want to know if there is a difference in the average dep_delay between United (UA) and Delta (DL) on flights leaving JFK for LAX. What is the appropriate test?

Which of these measures is robust to (not affected much by) outliers? Select all that apply

A model was fit to predict the Calories based on the sugars (g/cup) and Company.  There were 3 Companies (G = General Mills, K = Kellogg’s , and Q = Quaker). > summary(mod) Call:lm(formula = Calories ~ Sugars + Company, data = Cereal) Residuals:Min                    1Q            Median           3Q                  Max -39.697        -25.414          -1.459          16.559             55.349 Coefficients:                        Estimate        Std. Error        t value           Pr(>|t|) (Intercept)         85.3035          12.5365          6.804           3.2e-07 ***Sugars                4.3146            0.9556          4.515           0.000121 ***CompanyK          6.6755          11.2324          0.594           0.557443 CompanyQ         5.6221          13.5345          0.415           0.681266 —Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 Residual standard error: 27.41 on 26 degrees of freedomMultiple R-squared: 0.4442, Adjusted R-squared: 0.3801 F-statistic: 6.926 on 3 and 26 DF, p-value: 0.001405 Based on this output, which company had the HIGHEST  caloric content after Sugars were accounted for?

The probability model below describes the number of repair calls that an appliance repair shop may receive during an hour   Repair calls 0 1 2 3 Prob 0.10 0.30 0.40 0.20   What is the average number of calls received in an hour?

e-grocers sell groceries over the internet.  Customers enter their orders, pay by credit card, and receive delivery by truck.  A potential e-grocer analyzed the market and determined that the average order would have to exceed $85 if the e-grocer were to be profitable.  To determine whether an e-grocery would be profitable in one large city, she offered the service and recorded the size of the order for a random sample of 85 customers.   sample mean = $89.22 sample sd = $17.30 Suppose you ran all the numbers and got a p-value of 0.014, what is your conclusion at the 5% significance level?

Which of the following is a qualification a dental laboratory technician needs to perform his or her job duties?

What is the most commonly reported symptom of cancer treatment?