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list of 50 random phone numbers

WHAT IS WRONG and WHY?

1. A statistician is going to survey a sample of 50 people. He prepared a list of 50 random phone numbers generated by a computer. Next morning he came to work at 8:00 and began to make calls. By 11:00 a.m., his survey was done.
2. The United Nation declared that the world's six-billionth inhabitant was born on October 12, 1999 in Bosnia.
3. Jim Smart started a furniture business in December, 1998. During that month, his factory produced 50 tables. During the whole 1999, 1000 tables were made. In January 2000, Jim proudly announced, "During the last year we increased our production 20 times!"

TRUE OR FALSE (WITH JUSTIFICATION)?

1. Class width = Upper limit of a class - Lower limit of the same class.
2. A class frequency may be equal to zero.
3. The data 9, 12, 18, 30, 25, 15, 8, 42, 29, 44, 31, 26 can be broken into 5 classes: 8-15, 16 - 23, 24 - 31, 32 - 39, 40 - 44. One of these classes is empty.

TRUE OR FALSE (WITH JUSTIFICATION)?

1. For a given data set, the mean and median are always nearly equal.
2. In the same set of data, two or more elements may have the same z score.
3. A negative z score is unusual.
4. For a set having only negative values, both the mean and standard deviation will be negative.

Solution Preview

WHAT IS WRONG and WHY?

1. A statistician is going to survey a sample of 50 people. He prepared a list of 50 random phone numbers generated by a computer. Next morning he came to work at 8:00 and began to make calls. By 11:00 a.m., his survey was done.

In this case the sample surveyed will be less than 50 because when a computer generates random telephone number it is possible that some (or maybe most) of those numbers are invalid - thus no respnse will be achieved.

In order to actually survey 50 people, one would need a lot more than 50 random numbers

2. The United Nation declared that the world's six-billionth inhabitant was born on October 12, ...

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