Explanation:
If the testing firm rejects the null hypothesis at the 0.10 level of significance, it means that they have found evidence that suggests that the publisher's claim of 43% ownership of personal computers among readers is inaccurate.
Since the null hypothesis always assumes that there is no statistically significant difference between the observed data and the expected data, rejecting it means that there is a statistically significant difference between the observed data and the expected data. In this case, it means that the proportion of readers who own a personal computer is significantly different from 43%.
However, it is important to note that rejecting the null hypothesis does not necessarily prove that the publisher's claim is completely false or inaccurate. It only suggests that there may be reason to question its accuracy. Further investigation and testing would be needed to establish a more confident conclusion.