Option 2 because it is the opposite
Answer and Step-by-step explanation: The null and alternative hypothesis for this test are:


To test it, use F-test statistics and compare variances of each treatment.
Calculate F-value:



F = 1.8356
The <u>critical value of F</u> is given by a F-distribution table with:
degree of freedom (row): 20 - 1 = 19
degree of freedom (column): 20 - 1 = 19
And a significance level: α = 0.05
= 2.2341
Comparing both values of F:
1.856 < 2.2341
i.e. F-value calculated is less than F-value of the table.
Therefore, failed to reject
, meaning there is <u>no sufficient data to support the claim</u> that sham treatment have pain reductions which vary more than for those using magnets treatment.
To find the z-score for a weight of 196 oz., use

A table for the cumulative distribution function for the normal distribution (see picture) gives the area 0.9772 BELOW the z-score z = 2. Carl is wondering about the percentage of boxes with weights ABOVE z = 2. The total area under the normal curve is 1, so subtract .9772 from 1.0000.
1.0000 - .9772 = 0.0228, so about 2.3% of the boxes will weigh more than 196 oz.
Error is between steps 4 and 5. It should say:
Step 4: -9x < 27
Now divide by -9
Step 5: x > -3
Note that the inequality changes direction.
When you mean multiply or divide an inequality by a negative number, the inequality changes direction.
For example:
4 < 5
Multiply by -1:
-4 > -5
Another example:
-5 < 0
5 > 0
15f -8f+ 13= 55
⇒ 7f+ 13= 55
⇒ 7f= 55- 13
⇒ 7f= 42
⇒ f= 42/7
⇒ f=6
Final answer: f=6~