diff --git a/blinx/fluorescence_model.py b/blinx/fluorescence_model.py
index e3011d8..6ba6b15 100644
--- a/blinx/fluorescence_model.py
+++ b/blinx/fluorescence_model.py
@@ -73,11 +73,11 @@ def p_x_given_z(
     )
 
 
-def p_norm(x_tilda_left, x_tilda_right, loc, scale):
+def p_norm(x_left, x_right, loc, scale):
     # implimnetation of the normal distribution
 
-    cdf_left = jax.scipy.stats.norm.cdf(x_tilda_left, loc=loc, scale=scale)
-    cdf_right = jax.scipy.stats.norm.cdf(x_tilda_right, loc=loc, scale=scale)
+    cdf_left = jax.scipy.stats.norm.cdf(x_left, loc=loc, scale=scale)
+    cdf_right = jax.scipy.stats.norm.cdf(x_right, loc=loc, scale=scale)
 
     return cdf_right - cdf_left
 
diff --git a/blinx/hyper_parameters.py b/blinx/hyper_parameters.py
index b0e99c6..147e17c 100644
--- a/blinx/hyper_parameters.py
+++ b/blinx/hyper_parameters.py
@@ -1,4 +1,5 @@
 from .parameters import Parameters
+import jax.numpy as jnp
 
 
 def create_step_sizes(*args, **kwargs):
@@ -84,6 +85,7 @@ def __init__(
         num_x_bins=1024,
         p_outlier=0.1,
         delta_t=200.0,
+        param_min_max_scale=5, # how many sigmas away from mean should the model consider
         r_e_loc=None,
         r_e_scale=None,
         r_bg_loc=None,
@@ -106,6 +108,9 @@ def __init__(
         self.num_x_bins = num_x_bins
         self.p_outlier = p_outlier
         self.delta_t = delta_t
+        
+        # priors
+        self.param_min_max_scale = param_min_max_scale
         self.r_e_loc = r_e_loc
         self.r_e_scale = r_e_scale
         self.r_bg_loc = r_bg_loc
@@ -127,3 +132,15 @@ def __init__(
             raise RuntimeError("Both mu_loc and mu_scale need to be provided")
         if sum([sigma_loc is None, sigma_scale is None]) == 1:
             raise RuntimeError("Both sigma_loc and sigma_scale need to be provided")
+        
+        # need to define bin sizes for norm.cdf to get actual probabilities from priors
+        if r_e_loc is not None:
+            self.r_e_bin = r_e_loc / num_x_bins
+        if r_bg_loc is not None:
+            self.r_bg_bin = r_bg_loc / num_x_bins
+        if g_loc is not None:
+            self.g_bin = g_loc / num_x_bins
+        if mu_loc is not None:
+            self.mu_bin = mu_loc / num_x_bins
+        if sigma_loc is not None:
+            self.sigma_bin = sigma_loc / num_x_bins
\ No newline at end of file
diff --git a/blinx/trace_model.py b/blinx/trace_model.py
index 348bb60..8093a26 100644
--- a/blinx/trace_model.py
+++ b/blinx/trace_model.py
@@ -21,33 +21,45 @@ def log_p_parameters(parameters, hyper_parameters):
     log_p = 0.0
     if hyper_parameters.r_e_loc is not None:
         log_p += jnp.log(
-            norm.pdf(
-                parameters.r_e, hyper_parameters.r_e_loc, hyper_parameters.r_e_scale
-            )
+            p_norm(
+                parameters.r_e - hyper_parameters.r_e_bin/2,
+                parameters.r_e + hyper_parameters.r_e_bin/2,
+                hyper_parameters.r_e_loc,
+                hyper_parameters.r_e_scale)
         )
     if hyper_parameters.r_bg_loc is not None:
         log_p += jnp.log(
-            norm.pdf(
-                parameters.r_bg, hyper_parameters.r_bg_loc, hyper_parameters.r_bg_scale
-            )
+            p_norm(
+                parameters.r_bg - hyper_parameters.r_bg_bin/2,
+                parameters.r_bg + hyper_parameters.r_bg_bin/2,
+                hyper_parameters.r_bg_loc,
+                hyper_parameters.r_bg_scale)
         )
     if hyper_parameters.g_loc is not None:
         log_p += jnp.log(
-            norm.pdf(parameters.gain, hyper_parameters.g_loc, hyper_parameters.g_scale)
+            p_norm(
+                parameters.gain - hyper_parameters.g_bin/2,
+                parameters.gain + hyper_parameters.g_bin/2,
+                hyper_parameters.g_loc,
+                hyper_parameters.g_scale)
         )
     if hyper_parameters.mu_loc is not None:
         log_p += jnp.log(
-            norm.pdf(parameters.mu_ro, hyper_parameters.mu_loc, hyper_parameters.mu_scale)
+            p_norm(
+                parameters.mu_ro - hyper_parameters.mu_bin/2,
+                parameters.mu_ro + hyper_parameters.mu_bin/2,
+                hyper_parameters.mu_loc,
+                hyper_parameters.mu_scale)
         )
-    
     if hyper_parameters.sigma_loc is not None:
         log_p += jnp.log(
-            norm.pdf(parameters.sigma_ro, hyper_parameters.sigma_loc, hyper_parameters.sigma_scale)
+            p_norm(
+                parameters.sigma_ro - hyper_parameters.sigma_bin/2,
+                parameters.sigma_ro + hyper_parameters.sigma_bin/2,
+                hyper_parameters.sigma_loc,
+                hyper_parameters.sigma_scale)
         )
 
-    # sigma is a uniform prior distribution and will add a constant to all models --> we leave it out
-    # log_p_sigma = jnp.log(1.0 / (hyper_parameters.sigma_max - hyper_parameters.sigma_min))
-
     # We don't model a uniform prior distribution for p_on and p_off, because with bounds 0-1 it reduces to 0
 
     return log_p