4. Researchers working for a sports drink company would like to know if a new blend if its popular sports drink can help improve marathon runners' final running time. Marathon times, Y, are known to follow a Normal distribution. Suppose that runners using the old blend sports drink have a mean finishing time of 300 minutes = 300 minutes). A random sample of 20 runners was selected to use the new blend of sports drink in a marathon, finishing with an average time of 270 minutes and a standard deviation of 20 minutes (y = 270 min, s = 20 min). Can it be claimed that the new blend lowers finishing times? Or is it possible that random chance alone can explain the discrepancy? Carry out a hypothesis test of the true mean u using the 4- step procedure. Set your alpha-level to 0.05. b. Which is the correct alternative hypothesis? Oi. HA: H = 300 min %3D O ii: HA: H = 270 min O ii. HA: H < 300 min

Dogsled drivers, known as mushers, use several different breeds of dogs to pull their sleds. One proponent of Siberian Huskies believes that sleds pulled by Siberian Huskies are faster than sleds pulled by other breeds. He times 4040 teams of Siberian Huskies on a particular short course, and they have a mean time of 7.77.7 minutes. The mean time on the same course for 4747 teams of other breeds of sled dogs is 6.26.2 minutes. Assume that the times on this course have a population standard deviation of 1.51.5 minutes for teams of Siberian Huskies and 1.61.6 minutes for teams of other breeds of sled dogs. Let Population 1 be sleds pulled by Siberian Huskies and let Population 2 be sleds pulled by other breeds.   Step 1 of 2 :   Construct a 95%95% confidence interval for the true difference between the mean times on this course for teams of Siberian Huskies and teams of other breeds of sled dogs. Round the endpoints of the interval to one decimal place, if necessary.

A recent study revealed that the average weight of babies born in the United States is normally distributed with a mean of 7.5 pounds. This number is lower than recent years and so researchers are interested in determining what factors are associated with lower birth weights. One researcher decides to look at the age of the mother to determine if younger mothers have babies that are significantly heavier or lighter than average. To study this the researcher collects data from 87 babies who were born to mothers between the ages of 16 and 18. Only one baby was measured per mother. Twins and other multiple births were excluded. The average weight for these babies was 7.3 pounds with a standard deviation of .6 pounds. Was the average weight of babies of young mothers significantly different than babies in the general population?     No, the difference was not significant     Yes, they were lighter.     Yes, they were heavier

The data in the attached image represents blood pressure based on a new trial medication used in an experiment involving a total of 50 male and female subjects.  There were two levels of treatment: 0 = placebo and 1 = treatment group. Family History Blood Pressure = Fam-Hist-BP; from the paternal side = PS; from the maternal side = MS; from both sides = BS; none on both sides or not known = N.; Blood pressure before the experiment = BP-Before-Exp; Blood pressure after the experiment = BP-After-Exp. Task: Construct a histogram to represent the family BP history, the subjects' BP before treatment and the subjects' BP after treatment.

A father is concerned that his teenage son is watching too much television each day, since his son watches an average of 2 hours per day His son says that his TV habits are no different than those of his friends. Since this father has taken a stats class, he knows that can actually test to see whether or not his son is watching more TV than his peers The father collects a random sample of watching times from boys at his son's high school and gets the following data: 1.9, 2.3, 2.2, 1.9, 1.6, 2.6, 1.4, 2.0, 2.0, 2.2 Find a 95% confidence interval for the true mean number of hours teenagers at that school watch TV. a. Confidence Interval b. Conclusion

A researcher believes that among the residents of a remote community, 30% have type O blood, 50% have type A blood, 10% have type B blood and 10% have type AB blood. She takes a random sample of 80 residents and finds that 20 had type O blood, 40 had type A blood, 12 had type B blood and 8 had type AB blood. Do the data follow the hypothesized distribution of blood type for this community? Test at a = .05. Round your answers to three decimal places, if necessary. Null hypothesis: Ho: Po = 0.3, PA = 0.5, PB = 0.1, PAB = 0.1 20 40 12 8 80 80 80 80 1 1 1 20 40 8 Ho: Po = Ho: Po = Alternative hypothesis: Ho: Po = PA = PB = PAB = Ha: po # Type O 1 Ha: Po PA PB = PAB = 4 20 › PA = PA = Type 0 20 24 40 80 80 Ha: Po 0.3, PA # 0.5, PB At least one of the proportions is different. Complete the table of observed counts: Type O , PA # 0.667 Type A PB = PB = 40 Type A 40 What is the test statistic? 2.667 1 ,PB # 0 , PAB = 1 12¹ PAB Complete the table of expected counts under the null hypothesis: 12…