What is our Decision?

C

This falls beyond the critical value of 1.645. Therefore it falls in the rejection region.

In statistical hypothesis testing, the 1% level of significance (also known as alpha) is a predetermined threshold used to make a decision about whether to reject or fail to reject a null hypothesis (Ho).

In this case, the computed value of z is +6.00. To determine our decision, we need to compare this computed value to critical values associated with the significance level.

The z-score represents how many standard deviations an observed value is from the mean in a normal distribution. A positive z-score indicates that the observed value is above the mean.

Since the computed value of z is +6.00, it is extremely large and far from zero. In a standard normal distribution, the critical value for the 1% level of significance is typically around ±2.58. This means that if the computed value of z falls beyond ±2.58, it is unlikely to occur by chance alone and provides evidence against the null hypothesis.

Given that +6.00 is well beyond the critical value of ±2.58, we can conclude that the computed value falls in the rejection region. Therefore, our decision is to reject the null hypothesis (Ho).

Hence, the correct answer is C. Reject Ho.