what does the phrase "statistically significant" mean?

[san2612]

The paragraph:

The relationship of story elements found in children’s generated stories to reading achievement was analyzed. Correlations ranged from .61101 (p=.64) at the beginning of first grade to 83546 (p=24.) at the end of first grade, to .85126(p=21) at the end of second grade, and to .82588 (p=.26) for fifth/ sixth grades. Overall, the correlation of the story elements to reading achievement appeared to indicate a high positive correlation trend even though it was not statistically significant

• which of the following is the most complete and accurate definition of the term statistically significant is used in the paragraph?

A consists of important numerical data
B is educationally significant
C departs greatly from chance expectations
D permits prediction of reading achievement by knowing the story elements
E indicate two measures (reading achievement and story elements) gives the same information.

The answer is D but I don't understand what "statistically significant" mean in this passage.I searched google and found that
In statistics, a result is called statistically significant if it is unlikely to have occurred by chance.
but it's not relative to what's stated in choice D

 

[apex2000]

To be statistically significant something has to relative to a larger number of the same. So, if we were told that 50,000 people died this winter then that could only be considered against the total population because we have no other data. To be statistically significant the percentage needs to be at least 1% and above. From the above fictional example 50,000 is roughly 0.0007% of the population (65million) and would be considered as insignicant.

Next you need to define your data to get a number that relates to something much more specific. So far this winter I heard a quote that 39 people had died from flu. Of those most had died from the H1N1 virus and just 3 from other strains of flu.

So we could take the 36 and compare that to the previous year(s) to see if it is significant, and we could also compare the three to the total of 39. In the latter case we have a 7% (approx) result and therefore that is statistically significant for compiling data and future measurements, BUT only as a percentage of the total number of all cases of flu.

Now take the 36. Let us assume that during the same period last year 50 people died from the H1N1 virus. So this year the result of 72% is significant and any report would say that this year the number of deaths from the H1N1 is lower and only 72% against the previous year. That is a result which is statistically significant. But taking that figure against the total population it would be such a small percentage that it would be statistically INsignificant.

So, to be statistically significant you first need to be comparing like with like and then the result has to be of a size that makes it significant against the total in that particular group. I hope this will help you in understanding your question.

 

[Abstract Idea]

----- Not an English teacher -----

The answer is D but I don't understand what "statistically significant" mean in this passage.I searched google and found that
In statistics, a result is called statistically significant if it is unlikely to have occurred by chance.
but it's not relative to what's stated in choice D

In this text, "statistically significant" means exactly what you said "unlikely to have occurred by chance."

By analyzing the data, you see that the Pearson correlation coefficient tends to enhance with the grade. The closer to one the correlation coefficient is the more correlated the data are. However, that correlation measure was not statistically significant in the sense that the p-value was high. The p-value measures the statistical significance and it should be much lower to indicate that those data were unlikely to have occurred by chance.

So if you want to predict reading achievement by knowing the story elements you should have a correlation between the two variables. By these measurements it seems they are indeed correlated, but what if it just happened by chance?

 

[Raymott]

The paragraph:

The relationship of story elements found in children’s generated stories to reading achievement was analyzed. Correlations ranged from .61101 (p=.64) at the beginning of first grade to 83546 (p=24.) at the end of first grade, to .85126(p=21) at the end of second grade, and to .82588 (p=.26) for fifth/ sixth grades. Overall, the correlation of the story elements to reading achievement appeared to indicate a high positive correlation trend even though it was not statistically significant

• which of the following is the most complete and accurate definition of the term statistically significant is used in the paragraph?

A consists of important numerical data
B is educationally significant
C departs greatly from chance expectations
D permits prediction of reading achievement by knowing the story elements
E indicate two measures (reading achievement and story elements) gives the same information.

The answer is D but I don't understand what "statistically significant" mean in this passage.I searched google and found that
In statistics, a result is called statistically significant if it is unlikely to have occurred by chance.
but it's not relative [relevant] to what's stated in choice D

Yes it is relevant. If a positive correlation between A and B is not a chance finding, then the correlation is real, and A can be used to predict B.
Note, this 'prediction' is only to the extent of the correlation. If the correlation is 80%, you can't expect a 100% prediction of B, knowing A.

Here's a 100% correlation: All cats are feline. This is not a chance event, and you can predict that if you have a cat, you have a feline animal.

Here's an 80% correlation. 80% of sheep are white. If this is from a statistically significant study, and if you take a random sheep, you can predict with 80% likelihood that the sheep will be white.