Final answer:
To find P(Z ≥ -1.21), subtract the cumulative probability P(Z < -1.21) from 1, which can be found using a z-table or a calculator like the TI-83 or TI-84 series.
Step-by-step explanation:
The question asks to find the probability P(Z ≥ -1.21) for a random variable Z with a standard normal distribution. To find this probability, we need to calculate the area under the normal distribution curve to the right of Z=-1.21. Since most z-tables give the area to the left, we can use the symmetry of the normal distribution to understand that P(Z ≥ -1.21) is equal to 1 - P(Z < -1.21).
By looking at a z-table or using a calculator with statistical functions like the TI-83, 83+, or 84+, we can find P(Z < -1.21) and then subtract this value from 1 to get the desired probability. If we are using a calculator, a command such as invNorm(0.5+0.5*(1-P(Z < -1.21))) may be used.
For the standard normal distribution, a Z score of -1.21 corresponds to an area to the left that can be found in a z-table, which would then be subtracted from 1 to give the final probability that Z is greater than -1.21.
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