The average credit card debt for a recent year was $9205. Five years earlier the average credit card debt was $6618. Assume sample sizes of 35 were used and the population standard deviations of both samples were $1928. Find the 95 % confidence interval of the difference in means. a) Which formula will you use for this problem? Za/2 On = E P2 92 < pi – P2 < (P1 – P2) + Za/21 Ib. Id (ê1 – P2) – za/2 n2 n2 O – Za /2 <µ<ã + %a / 2 O (ĩ1 – T2) – ta /2 ° < H4 - H2 < (ã1 – ¤2) + ta/2 ' n2 n2 V n1 O (T1 – T2) – Za/2° < µi – µ2 < (@1 – 2) + za / 2 ° n2 n2 OI - ta/2 < µ < ¤ + toa/2 /n Op - za/2

4.1

A researcher is trying to estimate the population mean (μ) of anxiety based on his sample of n = 16 scores. His sample M = 58 and the s = 5.36. Construct the 95% confidence interval for μ.

Step 1 of 3. State the null and alternative hypotheses for the test.   Step 2 of 3. Compute the value of the test statistic. Round your answer to three decimal places   Step 3 of 3. Draw a conclusion and interpret the decision.

The tensile strengths of two types of materials were investigated by collecting 16 samples of each material (totally 32 samples).The sample mean for material 1 was 423.08 (psi), and for material 2 was 424.7 (psi). The samplestandard deviation of the difference in tensile strengths was sD = 2.8 (psi). Is there sufficientevidence to conclude that two types of materials have the same tensile strength? Formulate andtest the appropriate null H0 and alternative hypotheses H1 to verify the claim at level α = 0.01

A large population of 5,000 students take a practice test to prepare for a standardized test. The population mean is 140 questions correct, and the standard deviation is 80. What size samples should a researcher take to get a distribution of means of the samples with a standard deviation of 10?    provide the solution of above questions

The director of research and development is testing a new medicine. She wants to know if there is evidence at the 0.05 level that the medicine relieves pain in more than 388 seconds. For a sample of 67 patients, the meantime in which the medicine relieved pain was 390 seconds. Assume the standard deviation is known to be 17. Step 1 of 5 :   Enter the hypotheses: