The average speed of a baseball line drive is 83 miles per hour. Josiah practiced a new technique to improve his hitting speed. His coach recorded the speed of 42 random hits during practice and found that his average speed using the new technique was 84.2 miles per hour, with a standard deviation of 4.7 miles per hour. Part A: State the correct hypotheses Josiah is trying to prove the new technique is an improvement over the old technique.  Part B: Identify the correct test and check the appropriate conditions.

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A successful basketball player has a height of 6 feet 11 ​inches, or 211 cm. Based on statistics from a data​ set, his height converts to the z score of 5.17. How many standard deviations is his height above the​ mean?

You determine that the standard deviation for a sample of test scores is 0.  This tells you that 1 all the test scores must be 0. 2 all the test scores must be the same value. 3 there is no straight-line association. 4 the mean test score must also be 0. 5 you made a mistake because the standard deviation can never be 0.

You are interested in whether or not two different measures of child behaviour are different. The measurement tools both require the child teacher to fillout a question about the child, you give both questionares to Avery teacher and obtain two scores. On the CBCL, Avery score is is 68.On the BASC, Avery score is 32. The CBCL has a mean of 100 and a stardard deviation of 15. The BASC has a mean of 50 and a standard deviation of 10. (a) what is Avery z score on CBCL (b) What is Avery z score on BASC (c) On which test is Avery score lower relative to the population (CBCL/BASC) (d) The cutoff score for clinical diagnosis for both tests of -2 on either test are considerd  clinically signifcantly  concern. Do these tests give the same resultling diagnosis ? (yesy/no)

A golf analyst claims that the standard deviation of the​ 18-hole scores for a golfer is less than 1.2 strokes. State H0 and Ha in words and in symbols. Then determine whether the hypothesis test for this claim is​ left-tailed, right-tailed, or​ two-tailed. Explain your reasoning.

Raul received a score of 79 on a history test for which the class mean was 70 with a standard deviation of 7. He received a score of 79 on a biology test for which the class mean was 70 with standard deviation 9. On which test did he do better relative to the rest of the class? A. biology test B. history test     C. the same