Final answer:
The student is looking to find P(z < 0.21) in a standard normal distribution. They can use a normal probability table or a statistical calculator to find the probability associated with a z-score of 0.21, which typically represents the cumulative area to the left of z in the distribution.
Step-by-step explanation:
The student is asking for help with finding the probability P(z < 0.21) in a standard normal distribution. To find this probability, one has to calculate the z-score and then look up this value in a z-table, which usually shows the area to the left of the z-value. If the student has access to technology like a calculator or software that can compute these probabilities, they can use functions like invNorm on a TI calculator or equivalent functions in other statistical tools.
Using a standard normal distribution table, you would locate 0.21 in the z-column and find the corresponding probability. The value obtained from the table will be P(z < 0.21). If the table or technology resource indicates the area to the right, remember to subtract this value from 1 to get the area to the left, which represents the required probability.
It is important to note that all probabilities in a distribution sum to 1.0, and individual event probabilities must range between 0 and 1.