女性 * * 出血最常见的病因为
A．卵巢内分泌功能失调B．生殖器损伤C．生殖器炎症D．妊娠相关性子宫出血E．生殖器肿瘤
参考答案：A
A researcher is testing whether the average age of employees in a large firm is statistically different from 35 years ( either above or below). A sample is drawn of 250 employees and the researcher determines that the appropriate critical value for the test statistic is 1.96. The value of the computed test statistic is 4.35. Given this information, which of the following statements is FALSE The test:（）
A. is two- tailed.
B. indicates that the researcher will reject the null hypothesis.
C. has a significance level of 95%.
下列化合物中，化学性质最稳定的是（）。
A.正构烷烃
B.异构烷烃
C.正构烯烃
D.异构烯烃
