Question

29) What is the null hypothesis in this case?

A) Listening to music while studying will not impact memory.
B) Listening to music while studying may worsen memory.
C) Listening to music while studying may improve memory.
D) Listening to music while studying will not improve memory but can make it worse.

55) To check the production process of two dispensing soda machines, a random sample of 14 twelve ounce bottles was selected from each machine and the results are recorded in the following table. ounces

MACHINE A)12.1 12.7 11.6 12.1 12.2 11.4 12.3 11.8 12.1 11.7 12.5 11.5 12.4 11.6

MACHINE B)12.7 12.5 11.9 12.2 11.9 11.7 12.2 11.8 12.1 11.9 12.0 11.7 12.0 11.4

For each machine, compute the sample standard deviation 3 decimal places and then state the machine that is more consistent in dispensing the soda into the 12 ounce bottles.

Answer 1

29) The answer is

A) Listening to music while studying will not impact memory.

55). For calculating the standard deviation, we use the following formula:

For calculating the Sd, teherfore we need the squares of each observation and the total. We use the table below for doing the same.

	Macine A	Machine B	X^2	Y^2
	12.1	12.7	146.41	161.29
	12.7	12.5	161.29	156.25
	11.6	11.9	134.56	141.61
	12.1	12.2	146.41	148.84
	12.2	11.9	148.84	141.61
	11.4	11.7	129.96	136.89
	12.3	12.2	151.29	148.84
	11.8	11.8	139.24	139.24
	12.1	12.1	146.41	146.41
	11.7	11.9	136.89	141.61
	12.5	12	156.25	144
	11.5	11.7	132.25	136.89
	12.4	12	153.76	144
	11.6	11.4	134.56	129.96
Total	168	168	2018.12	2017.44

SD or Machine A:

The standard deviation for Machine A is 0.404 and for machine B is 0.332.

From the figurs above, we see that Machine B is more consistent in dispensing soda into the 12 ounce bottles.