Research Scenario Hematocrit levels (g/dL) from healthy term infants form a normal distribution with m = 61 and s = 7. Several studies have shown that the risk of anemia (indicated by low hematocrit...

Research Scenario

Hematocrit levels (g/dL) from healthy term infants form a normal distribution with m = 61 and s = 7. Several studies have shown that the risk of anemia (indicated by low hematocrit levels) is decreased with late cramping of the umbilical cord. Using clinical data, a researcher measured hematocrit levels from a sample of n = 100 healthy term infants with late cord cramping. The average hematocrit level (g/dL) for this sample was x̅


= 62. Do these data indicate that late cord cramping has a significant effect on hematocrit levels? Test with p=.05.

Note

µ = population mean

x̅ = sample mean

s = standard deviation

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Step 1: Set up your hypothesis and determine the level of significance

State the



null



hypothesis

1. In written format


2. In mathematical format
   
   

State the



alternative



hypothesis

3. In written format
   


4. In mathematical format
   
   

Step 2: Select the appropriate test statistic

5. The appropriate test statistic for the above scenario is the one-sample z test. What is a Z test? Describe why this is the appropriate test for the scenario?

Step 3: Set up the decision rule

6. Based on the level of significance you set in Step 1 (Question 5) and whether your alternative hypothesis is directional or non-directional, what is your decision rule? (In other words, what is your rejection region?)

Step 4: Compute the test statistic

7. Calculate the z statistic. Please show your work.


8. Do you reject or fail to reject the null hypothesis?
   


9. Does late cord cramping affect the hematocrit levels of healthy term infants?